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A closer look at one of the most common flaws that can affect both the performance and the appearance of ceramic glaze. In this episode, we break down the key causes, explain how they arise, and share practical ways to prevent them. For a deeper dive into the topic, check out…

What is rheology and what is it used for? This episode answers exactly these questions. Without delving into complex details, it presents a few key concepts to help navigate topics such as viscosity, material behavior, and process control. It’s a first step toward understanding…

Wettability is, in general terms, the property that describes a liquid's ability to adhere to a solid surface. It can also be understood as the process through which effective contact is established between a liquid and a solid. Wetting additives play a crucial role in creating…

The electrical conductivity of water is a key parameter in industrial production processes, as it reflects the amount of dissolved ions that can directly impact the stability and efficiency of operations. When conductivity levels go unchecked, they can compromise the quality of…

We dive into the essential role of chemical additives used during the grinding phase of ceramic glazes—a crucial step that sets the stage for successful application on the glazing line. We focus on dispersants and binders, compounds that give the glaze the right balance of…

Digital printing has transformed the ceramic industry, opening the door to highly sophisticated, versatile, and customizable designs. At the core of this shift are ceramic digital printers—advanced machines that use inkjet technology to precisely apply both functional and…

In the world of ceramics, temporary binders play a crucial role in improving the cohesion and workability of slips. These substances, often polymer-based, act on a chemical level by creating bonds between particles, increasing the mechanical strength of the mixture. In the…

This article takes inspiration from the thesis work of the Head of Research at Zschimmer & Schwarz Ceramco. The goal is not to focus on the specific topic explored in that study (in this case, the well-known issue of the "black core"), but rather to highlight the research…

In the field of ceramics, top glaze is defined as the glaze applied as the final layer on the still raw ceramic body. It can serve various purposes, but largely it is used on one hand to protect the underlying decoration and on the other to ptrovide the surface with specific…

After more than fifty episodes exploring topics of general interest—always through the lens of chemistry and ceramic production—we’ve decided to have some fun. We posed a few simple questions to artificial intelligence, asking it to write a short text about chemistry with…

Flux materials used in ceramics, often in glazes and digital glues, are capable of lowering the melting point of a material or compound, thus accelerating the sintering process. This action, which occurs through the breaking of the molecular structure of the compound (in our…

Industrial productivity is a top priority for any manufacturing enterprise, regardless of its field of operation. The ceramic industry, too, must adhere to rules and parameters that enhance productivity while avoiding any form of waste. However, process interruptions—representing…

In general, water quality is often a necessary precondition for any ceramic proaction process. For this reason, there are various processes capable of purifying water efficiently and, most importantly, safely. One of the most widespread and commonly used methods is reverse…

Suspending agents belong to a broad category of additives whose primary purpose is to provide ceramic suspensions (slips, glazes, engobes, or frits) with good internal stability, counteracting potential sedimentation phenomena. Available in both liquid and solid forms, these…

Complexing agents are capable of catching multivalent cations present in suspension to prevent them from negatively affecting the ceramic process. They are responsible for one of the main mechanisms underlying the deflocculation process: complexation. These are simplified and…

The topic of non-planar surfaces, which develop on multiple micro-levels and are sometimes improperly identified as 3D surfaces, plays a crucial role in giving ceramic surfaces not only a more natural appearance but also a broader and more extensive expressive potential. This is…

In the 6/2019 edition of Zi Brick and Tile Industry International, the first part of this article informed readers about the technical aspects of digital printing systems. This part of the article examines the necessary preparatory work and explains the file creation process. All…

At present, in the heavy clay industry, products are decorated mainly by applying engobe with the aid of scattered granules or by means of reduction effects created by the firing process. These techniques are suitable to produce traditional products for the existing market. What…

The operating temperature is an important parameter that ceramic producers must take into account in order to avoid application problems that can also negatively affect the quality of the finished product. However, this parameter is not always easy to manage, especially if we…

Most of the ceramic production processes depend on suspensions or more generally chemical dispersions of ceramic powder in a liquid, mostly water. In order to provide the suspension with the right features, small quantities of chemicals able to modify the rheology of the system…

All analysis of ceramic suspensions carried out by those companies that supply chemicals for ceramic production are fundamental to properly develop the processes that take place along the production line. Here is an overview about the role of these important investigations, with…

In ceramics, the use of chemicals plays a fundamental role in providing the final product with high technical and aesthetic results and in promoting a proper application process. However, their actions can be sometimes less effective or compromised. There are several reasons…

Glaze and grit suspensions are made up of a liquid part (usually made-up of water and one or more rheological chemicals) and a dispersed solid part. However, these two different suspensions show a lot of differences that may lead to very contrasting results, also implying a…

Cratering phenomena are defects that appear as microscopic craters on the surface of ceramic bodies on which an aqueous (and still drying) suspension has been discharged. It is an application problem that leads to a misalignment of the suspension due to the presence of one or…

CMC are organic compounds, water-soluble polymers derived from cellulose, widely used in several fields of industrial production. In ceramics, sodium CMCs perform multiple functions within suspensions and solutions and can be marked by very different properties depending on the…

The plasticity values of ceramic mixtures is a very important issue, since it affects the values and features of the mix and therefore the proper development of the ceramic production process. In general, the use of clays marked by high plasticity values is usually synonymous…

In ceramics, digital technology (use of digital glues and digital inks) has definitely riform the sector, making the production process much more flexible and expanding creative and aesthetic possibilities. The extraordinary precision with which the ink is discharged on the…

The term SEM is an acronym for Scanning Electron Microscope. This is a high-technological tool that, unlike optical microscopes that take advantage of light as a radiation, makes use of an electronic source (usually tungsten). It is a type of electron microscope that produces…

Sodium silicate is an inorganic substance that at room temperature it is in solid state. It is a chemical compound used in several areas of industrial production. In ceramics, sodium silicate is very effective within ceramic mixtures. Among the several effects it produces, it…

Polluting and odor emissions are two sensitive critical issues to which ceramic manufacturers have long been looking with considerable attention. This is a problem that appear in the final stage of the ceramic production cycle, inside the kilns, but whose origin is due to…

Among the several issues that may occur along the glazing line, the excessive foaming of the glaze is one of the most frequent and problematic. The phenomenon is already visible on the surface of the glaze inside the stirring systems but the consequences of its presence can…

Speaking of ceramic glaze applications and technical defects, one of the strangest and most interesting is the "TV effect". It consists of a preferential migration of the glaze towards the perimeters of the tile that produces in those areas a thickening of the glaze. The…

Viscosity (or viscous friction coefficient) measures a substance's attitude on generating friction between its layers. In other words, it defines the fluid resistance to its proper flow. The viscosity value of the barbottina can sometimes rapidly and suddenly change and in case…

All process water involved in ceramic production, both tap and well waters, usually contains a variable percentage of bacteria. And the same applies to inorganic raw materials used in the grinding process to produce the semi-finished products that will be later applied along the…

In the last few years the ceramic industry has been rapidly evolving thanks to the progressive digitalization of the some of the processes. In this regard, the digital ink decoration system plays one of the most important role. What is a digital ink for ceramic? What is its…

Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. In general, to get a proper glaze application, it is always important to work on the fluid's surface tension by decreasing or, more generally, adjusting it, until you…

In general, wet grinding systems as well as atomization systems, offer the best performance and the best production results only when chemical and physical features of slips are constant for the duration of entire process. More precisely, the optimal process is developed when the…

The Italian ceramic industry has been involved for years in a very important goal: the reduction of environmental impact. For this reason it is constantly tested in order to prove its right performances as well as to ensure compliance with the strictest standards. Formaldehyde…

Rheology is the science that deals with the flow and the strain rate of matter. It’s a branch of physics that studies the origin, nature and deformation’s characteristics of a matter under the influence of external forces, with particular regard to non-Newtonian liquids. Its…

The flocculation of ceramic mixtures is a problem marked by a progressive aggregation of the solid particles and it often takes place due to phenomena of electrostatic attraction between the clay micelles in suspension. This process leads to a significant increase in viscosity…

What do we mean with “dusting phenomena”? What are the features of a glaze marked by this characteristic? In general, we are talking about a glaze that shows a low cohesion after application by means of traditional airless spray systems. This lack of cohesion is not only…

Surface treatments’ target is to protect the surface, improving its performance without changing the basic features of the tile. More generally, tiles (treated or not treated) must comply with regulations and market’s target that can obviously change according to the client and…

This dissertation aims to refocus, from a special and provocative perspective, the role of chemicals used in ceramics: from the beginning to the end of the entire process, that is from the grinding of the clays that form the basis of the ceramic mixture up to the firing cycle. …

Ceramic glazes can be applied along the glazing line by means of different systems. The most popular and widespread is the airless spray system, even if vela and bell systems are still in use. Whatever is the choise made by ceramic producers, the glaze's rheology must be always…

Chemically speaking, water-based digital glues can be generally considered as organic polymers and inorganic components (when present) in water and polar solvents. Their chemical nature, unlike that of solvent-based digital glues, is firstly characterized by the elimination of…

There have been for years on the market different kind of DIGITAL GLUES for ceramic production, applied process by means of piezoelectric inkjet systems. Although each of them interacts with powders and/or grit in different ways, there are currently two main categories that must…

The black core is a more or less localized area characterized by a brown/black (or even white) color, clearly visible in the thickness of the final ceramic tile. Its presence is usually sign of inadequate oxidation and it has not to be considered a defect that compromise the…

The ink-jet decoration has surely eliminated several critical issues bringing out, however, new and more complex problems. Among them, the most popular concerns the water repellency phenomena that arise due to the lack of chemical compatibility between inks based on non-polar…

The ceramic mixture usually used in ceramic production, largely consists of inorganic raw materials (clay, feldspar, sand, etc.), grinding water and chemical. These mixtures, since they must be properly managed in the various stages of the production process - from grinding to…

As is well known, the ceramic mixture after being atomized is subjected, during the forming phase, to very high pressures (over 400 Kg/cm2) that are necessary for the creation of the ceramic body. The raw tile, even after pressing, contains a water amount (residual humidity)…

The ceramic glaze application is one of the most delicate steps of the ceramic production process. To get high levels of performance, the glaze must have accurate rheological characteristics that take into account the specific and different application conditions of the…

The ceramic glaze application is one of the most delicate steps of the ceramic production process. To get high levels of performance, the glaze must have accurate rheological characteristics that take into account the specific and different application conditions of the…

The dry grit application system is a mode of the ceramic production process that companies are looking at with increasing attention and that somehow has already found its circulation thanks to the wide use of digital systems that focus not only on the application of inks but also…

Ceramic glaze application – both before and after the digital printing process – mostly occurs by means of analogical systems (spray wet application). For some time, however, new kind of machines that do not leverage digital technology (inkjet – piezoelectric) has joined the…

The mechanical resistance value of raw ceramics tiles is normally regulated by the UNI EN ISO 10545/4 and it is measured by a device that is called chrometer. This is a specific precision tool that is able to define the breaking load and the flexural strength of the ceramic…

Following the ceramic body forming stages and subsequent digital printing steps, the ceramic production process involves a final application of grits or glazes, sometimes in significant amounts. Failure to apply the correct process parameters can sometimes lead to issues in…

Antibacterial protections, already used in several fields of industrial production, had become in more recent times a central issue of ceramic tile’s production. Market interest, also pushed by the recent events, has speeded up the research within the labs in order to boost a…

Grit suspensions applied by means of spray systems applications are usually prepared in the glazes’ grinding department. The three main ingredients of the suspension are poured inside tanks provided with stirrers.

As we all know, lapping and polishing processes that are necessary to provide ceramic tiles with the required aesthetic features, both involve the removal of a very thin layer of glaze that is on the very external part of the tile.

Process water play a very important role within ceramic activities, being involved in a wide range of production’s steps. If one the one hand they are strictly necessary to the course of the work, they can lead on the other hand to problems when they do not fits the required…

In ceramic, semi-finished products are all those materials (in our case, aqueous suspensions) that are produced beside the main production line and that are used in several phases of the process, mostly along the glazing line.

As many know, slurries (the mix or SUSPENSION of water, clays and raw materials that form the basic ceramic mixture) before being processed within the atomizers, can rest for shorter or longer time inside storage tanks, where they undergo to a slow and constant stirring action in…

During firing cycle, tiles usually start to gradually and constantly heat up. During the heating process, it obviously starts the water evaporation process. Water that is present both on the surface and (overall) inside the ceramic body.

Silver is a noble metal with a long-standing tradition. It is a trace element even present in organism’s tissues. Even though in small quantities, it is also taken by humans through food. Silver is being used in many medical and industrial applications as well as in different…

Due to the recent events that have brought to public attention the increasingly tightening requirements in terms of cleaning and health protection, the ceramic district - that for some time has been offering to the market surfaces with “anti-bacterial properties” - is working…

Ceramic industry is today inseparably linked to the use of digital printer machines that involve the use of pigmented liquid inks. These new production systems have therefore required the development of specific mediums able to improve the printing process in terms of definition…

Changes in taste perception together with the evolution of high performing and sophisticated production technologies, have led to the assertion on the markets of ceramic surface that aesthetically reproduce a wide range of natural materials.

Chemical additives allow and promote the proper performance of almost all the ceramic production processes. Their importance has been exponentially raising with the coming of the rapid firing cycles that have increased the companies’ productivity, leading to a cost containment. …

All waters used in ceramic processes, both tap and well water, contain bacteria and microorganisms. The same goes for the inorganic raw materials involved in the milling process: frits, clays, feldspar, nefeline, etc… On this basis, bacterial proliferations can potentially…

The ceramic industry has recently shown an interest in some of the latest generation glass grits, to be used as final cover on all those product - tiles or slabs - that are subsequently destined for lapping or sanding process.

As already highlighted in the news dedicated to grinding water ( What characteristic the grinding water should have to yield a dense slurry? ), controlling the electrical conductivity is essential in order to avoid rheological problems inside the slurry. The grinding water…

The issue of smell and polluting emissions deriving from the firing ceramic process is still a critical topic. In order to understand and solve the problem, it must look at the root of what’s causing it: the chemical composition of digital inks.

The use of additives in the ceramic production process – specially added to glaze or slurry – is now essential in order to obtain a product with high technical performance and refined aesthetic features marked by attention to detail.

To calculate the picoliter volume of an ink drop discharged by a single nozzle of an inkjet head print it is necessary to make a couple of simple calculation that keep in mind the following variables

The wet system requires the use of specific medium. On the other side, the dry application takes place using special machines (shot blasting applicators) that can work with two different technologies (roller or belt), both with the same purpose: spreading uniformly the grit on…

The end-of-line protective treatment – which is recommended after the lapping/polishing process – preserve the ceramic surface from stains and dirt, and it improves the surface’s performance avoiding possible chemical aggressions.

The polishing or lapping process can make the surface delicate and more sensitive: to chemical agents = detergents or aggressive cleaning products to food = lemon juice, coffee, tomatoes

The use of ceramic spray booth is the most widely used method for the wet full field application of grit.

Digital glues, whether water or solvent based, have the ability to fix the glass grit to the ceramic support. However, in case of full field application (when the amount of grit can reach 600/800 grams per square meter), the glue is not able to bind the entire layer of grit.

The use of water-based digital adhesives facilitates the application (even simultaneous) of low, moderate and high quantities of grit.

Solvent based digital adhesives, like all bulk digital inks, tend to expand in contact with the substrate, thus losing the definition of the grit. Water based digital adhesives have 2 components: alpha and beta. These 2 components, once applied, react very rapidly to create a…

The vitreous covering which protects the tiles offers very high performance in terms of resistance to stains and chemical agents. Grinding removes a certain amount of glaze from the surface with the grinding machine disks, creating a very flat surface with a matt or reflective…

Despite the considerable benefits of digital inks in ceramic manufacturing, there are some important counterindications. In particular, the increase in polluting emissions and bad odours during combustion of solvent based inks, which is a problem for people living nearby the…

Digital inks have had considerable benefits for ceramic decoration, especially in relation to the definition of the graphics. However, the conditions for application of the inks do not always allow an adequate definition to be obtained, especially when intense colourations are…

Ceramic companies are increasingly feeling the need to reduce the water consumption of their glazing lines. This is mainly due to the fact that the residual humidity of tiles entering the kiln must be controlled to stop them exploding during pre-firing: the water generates a…

Digital inks designed for decorating tiles with ink jet printers contain apolar solvents. The glaze applied as a finish coat after decoration is water based, and hence contains polar (and also non-toxic) substances, in contrast with the inks. The difference in polarity in the…

Ceramic glazes and their application systems have not undergone significant change in recent years. In any case, there are various types of additives for levelling the glaze and which can be used in various ways depending on the type of application and the characteristics of the…

The mechanical strength of ceramic tiles and slabs – dried or green – is critical to avoid reducing production. Reductions in production caused by breakages and other defects are often only visible after firing. The advent of digital decoration technology has gradually changed…

The water used for grinding ceramic pastes plays a fundamental role in making a high density slurry with constant characteristics over time. The on-going challenge in ceramics is to maximise the density of the slip to increase production and reduce the energy cost of…

The aqueous suspensions in glazes and all ceramic clay suspensions are prone to attack by bacteria, mould and fungi because they contain large amounts of water, organic products contained in the clay and organic raw materials or additives. These are nutrients for micro-organisms.…

When water based inks are used in an ink jet printer, the result is a higher definition image. A drop of solvent based ink is composed of 35% pigment and 65% apolar solvents. A drop of water based ink, on the other hand, is composed of 33% pigment, 33% water and 33% non-toxic,…

During combustion, solvent based inks release strong odours which are perceptible by people. Water based inks have now been developed which do not release perceptible combustion odours. What are the differences between the two types of ink that make them behave so differently?

When ink jet print heads are kept in standby for a period of time, the ink at the nozzle outlets is exposed to air. Neither solvent nor water based inks dry on the head.