Sintering involves heating and applying pressure to particles of material until they bind into an organized mass – similar to when you press snow together into a compact snowball.
Reaction bonded and liquid phase pressureless sintered sic offers excellent shape capability at lower processing temperatures for complex shapes. Unfortunately, their bending strength begins to diminish rapidly once temperatures exceed 1400degC.
Hårdhet
Sintered silicon carbide (SSIC) is a non-oxide ceramic with excellent hardness, density, thermal conductivity and wear resistance properties that is well suited for vehicle armor plates to protect military personnel against high velocity projectiles. Our team can manufacture these plates to provide your military vehicles and personal protective equipment with maximum safety against potentially lethal projectiles and minimize collateral damage in hostile environments.
Liquid phase pressureless sintering is an alternative densification method that uses infiltrating liquid silicon and silicon alloy into green bodies of a-SiC particles with liquid silicon to form b-SiC which then reacts with existing a-SiC to densify them and create products with precise dimensions and high purity levels, but poor high temperature performance due to the presence of b-SiC which compromises strength, acid corrosion resistance, flexural strength and more. This process can produce products with precise dimensions and purity levels but may affect strength flexural strength as well as acid corrosion resistance.
In order to improve the high-temperature performance of reaction sintering, it is necessary to control residual Si size and distribution within the body. This can be accomplished by adding sintering aids into the process and altering their composition – producing a-SiC particles with narrow distribution and low porosity that allows a high bending strength bending test performance – up to three times higher than commercial RS-SiC!
Motståndskraft mot korrosion
Corrosion of sintered SiC ceramics causes surface flaws that degrade strength at elevated temperatures, particularly at brittle fracture under mechanically or thermally-induced stress. Corrosion shortens material lifespan reducing strength significantly above 1400deg C due to corrosion effect – this phenomenon results in rapid drop off in strength of conventional reaction- and pressureless sintered SiC ceramics (Table 16).
This invention provides a sintered body of silicon carbide containing a-type silicon carbide as its main constituent. To produce this material, a-SiC powder and graphite are mixed together with steel billet to form a porous product which then undergoes vapor phase Si infiltration to seal its pores and sinter it, yielding an end product comprising mostly a-form silicon carbide that displays excellent corrosion resistance when subjected to nitric acid washing.
An advancement of this technology lies in its capacity to produce solid-state sintered materials with high densities and room temperature bending strengths in excess of 580 MPa – nearly double those typically produced through reaction sintered SiC. To enhance this material’s performance, only coarse connected grains were sintering during original reaction sintering particle sintering and fine SiC particles reduced to minimum levels while keeping corrosion resistance improved with an enhanced additive (Y2O3) used during production.
Motståndskraft mot slitage
Silicon Carbide is one of the hardest ceramic materials, maintaining its hardness and strength at high temperatures for exceptional wear resistance. Furthermore, its excellent thermal conductivity aids corrosion resistance as well as thermal shock. Furthermore, this light material weighs half as much as steel with an extremely low thermal expansion rate making it suitable for use in harsh applications and environments.
Morgan’s premium sintered sic grades such as Hexoloy SP and Purebide are designed to meet the stringent requirements of mechanical seal faces that require hardness, strength, wear resistance, chemical and corrosion resistance and increased lubrication between mating surface surfaces – outperforming conventional reaction bonded and sintered sic products in performance and longevity. They feature spherical pores designed as fluid reservoirs to further increase performance lubrication between seal surfaces for improved lubrication between them and outperforming conventional reaction bonded sintered sic products in terms of overall performance and longevity.
Durability makes this material ideal for aerospace components like fuel and oil systems, with its chemical resistance protecting it against common acids, salts and alkalis. Furthermore, its low density saves weight contributing to improved fuel efficiency and performance on aircraft. Other industrial applications for this material include semiconductor production equipment parts, lasers and fusion reactor structural applications.
Styrka
Sintered silicon carbide is a durable ceramic material, known for its hardness and density which make it suitable for ballistic armour plates in vehicles or personal protection systems, providing protection from high velocity projectiles while still maintaining mobility without compromising protection. These plates’ high density can even help keep weight low for increased mobility without any reduction in protection levels.
Sintered sic strength is determined by both its sintering process and particle size distribution, and any residual silica present during sintering that could compromise its hardness and wear resistance. To prevent this, sintering must take place under an inert atmosphere using gasses such as argon or carbon monoxide (CO) as sintering aids and/or boron carbide or carbon (B4C) sintering aids as inerting agents.
Pressureless sintered SiC, hot isostatic pressing sintering and reaction bonded SiC can differ significantly in terms of density and flexural strength. Pressureless sintered SiC is generally stronger than reaction bonded SiC due to its superior resistance to heat and chemical attack; however, reaction bonded SiC may be more cost effective for applications that do not demand as high of performance levels. Sintering additives containing Re2O3 (Re = Sc, Lu, Yb and Er) at 2:3 mole ratio were found to significantly improve the high temperature strength of Liquid Phase Sintered and later annealed SiC ceramics by suppressing IGP formation – likely attributable to cleaner SiC-SiC and SiC-junction boundaries.
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