How is the ceramic tube made?
One of the methods is dry press, which is putting the power in tooling and put it into a dry press machine for a few minutes, tube is ready, this method is regularly used to make a tube.
Dry Press Manufacture:
1. Alumina power put into the tooling
2. Tooling put into the dry press machine
3. Final product ceramic tube
Zirconia Ceramic Peg For The Mixing Processing of Food and Beverage Industry
We got a query requested to develop ceramic milling and mixing components for the processing of the food and beverage industry, cause of the stainless steel occur metal impurities during the milling and mixing processing.
Materials Choose Step (Design Guide)
1. Food Safety
2. Chemical Resistance
3. Wear Resistance
4. Mechanical Strength
As per the above choice, our engineer recommended Zirconia Ceramic Material for this project.
* High Hardness
* Wear Resistance
* Chemical Resistance
* Excellent Mechanical Strength
Design Solutions
Zirconia Ceramic Screw Sleeve bonded with SSL304Shaft (Zirconia Ceramic Beg).
Brief Introduction
The zirconia ceramic peg is a part of a grinding mill machine, which using cerium stabilized zirconia oxide grinding beads (size: 1.6-1.8mm) for grinding mill and mixing processing, so it is requested the grinding pegs had a long life-time and food safety for the processing of food and beverage industry.
Our ceramic milling and mixing beg had been using for a year, they are still running and had a good effort.
The next products middle and small zirconia ceramic peg will be coming soon.
Our engineer team will develop various kinds of the ceramic peg, if there is any project enquire please feel free to get in touch Email: sales@innovacera.com.
Boron nitride is used for the electrode insulation of vacuum high-temperature equipment.
Matching model: BN-99, BN-AL
Advantage:
Innovacera can supply large size with 500*500.
And the 10 large-scale hot press sintering furnace is the largest production of high-purity boron nitride in China.
Classification of hot air guns: hot air gun with built-in fan; air gun without the fan.
The drypoint can reach 1200 ° C.
Using high-performance silicon nitride ceramics as the substrate, high-temperature mechanical strength, strong thermal shock resistance, acid and alkali corrosion resistance, both excellent insulation properties and good thermal conductivity, coupled with our company’s proprietary formula and heat Pressure manufacturing technology.
Hot air gun installation precautions:
There are several reasons why those who work in the aviation and aerospace industry are relying on silicon nitride. First of all, while this material is relatively new to this industry, current properties that are known make it suited to this space. These ceramics are strong, durable, resistant to heat, and lightweight. They provide economic value and are versatile, having been incorporated in multiple aircraft and spacecraft parts already. As technology continues to grow and progress in this space, flight speeds and demands are only going to increase. This material is able to withstand the growth and progress in these industries over time.
Silicon nitride has many key applications throughout the aviation and aerospace industries. In the past, traditional metals were used; however, the rapid development of this field has meant that existing metals cannot stand up to the stress of supersonic and hypersonic travel. Silicon nitride is better suited to withstand the incredible temperatures that develop at high velocities.
Si3N4 is already replacing legacy materials in:
The ability of silicon nitride ceramics to meet and exceed the demands and expectations of the aerospace industry only promises further growth and expansion of this material in this area.
Brazing-ceramic is a special case of joining materials.
The technologies developed to perform the joining of ceramics to themselves or to other materials are different from most other brazing processes.
Ceramics, as everybody knows, are hard and brittle with nil ductility, and limited tolerance for tensile stresses.
Therefore if possible, ceramics are designed to be stressed in compression.
Although used as thermal insulators, they are sensitive to thermal shocks.
However, within limits, their properties can now be adapted to intended uses, especially by including in the mass strengthening (reinforcing) particles, fibres or whiskers.
And also by causing process induced structural transformations to enhance their suitability to various applications.
The main differences in Brazing-ceramic as opposed to metals stem from the fact that most regular brazing materials do not wet ceramics.
This is due to the basic physical properties of these materials, like their strong ionic and covalent bonding.
Furthermore, as ceramics have greater thermodynamic stability than metals, strong chemical bonds to enhance adhesion are not easy to form.
In the present increasing use of ceramics, due to the economic importance of joining them, of the many different methods applicable to perform acceptable joints, the most important and adaptable is probably still Brazing-ceramic.
Earlier ceramics were intended to withstand service at room temperature, essentially displaying insulating properties and wear resistance (in absence of shocks).
The development of more advanced types was promoted by the challenge to confront service conditions at elevated temperatures, in oxidizing or corrosive environments with substantial mechanical properties.
In particular, there is a major drive to find uses for ceramic in thermal engines and in energy-producing facilities for recovering waste heat. All these may need Brazing-ceramic.
The new developments are now called structural ceramics to signify their ability to meet exacting requirements in demanding service conditions.
It should be noted that ceramics can be monolithic or ceramic matrix composites.
Within each type designation or family, say Alumina, various classes are included that, depending on processing parameters, may exhibit quite different structural and mechanical properties.
Another consideration to keep in mind is that it may be quite difficult if not impossible to get tabulated design properties from handbooks or manuals.
That is because test results depend heavily upon specimen preparation and size, and on the type of test.
Also, joint design can have much influence on the success of the Brazing-ceramic joining process.
The reason is the substantial difference in the Coefficient of Thermal Expansion (CTE) between ceramics and metals, a fact that may introduce high stresses and possibly cracks conducive to failures.
Only exceptionally one can find a ceramic having CTE in the range of some low-expansion metals, a quite rare and welcome occurrence for performing Brazing-ceramic successfully.
One strategy often employed for bridging the gap in CTE values consists in designing joints to be stressed in compression.
Or, for widely different values of CTE, to interpose intermediate materials to provide a gradual passage from the minimum to the maximum of that property.
To promote the wetting of ceramics by filler metal and its adhesion to the surface, the following techniques are used:
1) – Indirect Brazing-ceramic by first coating the ceramic surface in the joint with material, usually a metal, suitable to be wetted by a regular filler metal that would not wet untreated ceramic surfaces.
The metallic coating acts as a transition material between metal and ceramic. Care must be taken to avoid that the coating sintering heat cycle crack the ceramic.
Typical in this class is the well known Molybdenum-Manganese coating. A slurry of specially prepared powders is applied to the ceramic as a paint.
It is then fired in a hydrogen atmosphere furnace at about 1500 °C (2730 °F) that causes glassy materials from the ceramic to migrate to the metal powder bonding it to the surface.
Other applied coating techniques resort to physical vapour deposition (PVD) for sputtering metals. Brazing-ceramic is then performed with regular brazing filler metals suitable to the metal to be joined.
2) – Direct Brazing-ceramic by using Active Filler Metals containing special alloying elements. The addition to regular silver-based brazing alloys, of metals having a strong affinity for the elements constituting the ceramic, promotes wetting and adhesion.
Thus, metals having a strong affinity for oxygen, like titanium, aluminium, zirconium, hafnium, lithium, silicon or manganese help conventional brazing alloys in wetting oxide ceramics without special preparation.
Metals that react with silicon, carbon or nitrogen help wetting silicon carbide or silicon nitride. Quite a few Active Filler Metals were developed over the years for scientific investigations and some of these are available commercially from known manufacturers (GTE Wesgo, Degussa AG, Lucas-Milhaupt, Handy & Harman).
It seems improbable though, that off the shelf materials can be procured and used in new applications of standard Brazing-ceramic processes without thorough study and preparation.
Two other cases should be presented in this context due to their large diffusion. One is the brazing of carbide tips to steel shanks. Carbide tools are usually manufactured by sintering titanium-, tantalum- or niobium-carbide with a cobalt binder. Other carbides and other metal binders are also used.
Silver base brazing filler metals containing nickel, like BAg-3, BAg-4 and BAg-22 have been successfully used. Tungsten carbide tools need a special sandwich filler metal including a copper shim to reduce residual stresses.
The other case refers to Silicon carbide tools, brazed using a Titanium base filler metal, or a titanium-containing silver-copper or nickel-titanium brazing alloys.
In conclusion, Brazing-ceramic although not simple to perform is a necessity if the special properties of ceramic materials of the most diverse types have to be exploited in actual implements. A thorough study and experimental development must be devoted as needed to obtain successful results.
The Special Mid August Bulletin 64, attached to our Practical Welding Letter issue 96 for August 2011, includes a rich Resources List of Online Links to readily available Information on Ceramic Brazing.
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