Sintered Silicon Carbide

Silicon carbide is a high-performance ceramic with exceptional hardness, wear resistance and thermal conductivity properties. However, its complex geometry makes precise machining extremely challenging; diamond tools must be employed for maximum accuracy when working with it.

Saint-Gobain utilizes multiple manufacturing avenues to craft the highest-grade sintered silicon carbide products. We employ reaction sintering and pressureless sintering processes for fully densified ceramic products designed to stand up against rigorous applications.

High Strength

Silicon carbide ceramic is among the hardest and strongest available, maintaining its strength at high temperatures while remaining impact resistant. Due to this combination of hardness and strength, silicon carbide makes an ideal material choice for many demanding applications; in particular it is resistant to corrosion and oxidation while boasting low coefficient of thermal expansion as well as excellent tribological properties and being an electrical semiconductor.

Mascera’s VSiC and PGS-100 sintered silicon carbide materials for pump seals provide long-term durability in harsh environments that include corrosion and abrasion. Standard sizes and geometries of VSiC make them suitable for most types of pumps while PGS-100 has added graphite content which increases lubricity for improved PV capability between hardface mating pairs resulting in greater dry run survivability as well as increased sealing performance.

Reaction sintering (RS-SiC) is one of the most desirable manufacturing processes of silicon carbide due to its dense structure, low processing temperature, good shape capability and high purity. Unfortunately, mechanical properties such as strength and Young’s modulus of RS-SiC tend to be lower due to residual silicon (Si) size in its microstructure.

Pressureless Sintering of Silicon Carbide Ceramics (PS-SiC) is another method for producing silicon carbide ceramics, employing ultrafine SiC powder mixed with small amounts of sintering additives to form dense material with fine grains. It has excellent mechanical properties and forming methods, making this technique suitable for various applications.

High Stiffness

Silicon carbide (SiC), commonly referred to as one of the hardest ceramic materials available today. SiC is notable in that its strength and hardness remain constant even at very high temperatures, making it an extremely resilient material resistant to wear, corrosion and thermal shock – even more impressive is that its weight is half that of steel while boasting low coefficient of expansion and great thermal conductivity properties.

Sintered silicon carbide is produced by mixing fine and pure silicon carbide powder with non-oxide sintering additives, then compacting this powdered material using traditional ceramic forming processes such as isostatic pressing, die-pressing or injection molding. These methods of ceramic forming allow for the creation of highly complex shapes without compromising sintering properties.

Reaction bonded and pressureless sintering technologies for silicon carbide are two primary forms of sintering technology, both capable of creating extremely strong, hard and durable ceramics for high temperature applications; each type offers distinct characteristics which may make it suited for certain tasks or uses.

Saint-Gobain Performance Ceramics & Refractories’ Reaction Bonded Silicon Carbide (SSiC), produced through reaction sintering, offers exceptional chemical and mechanical properties at temperatures exceeding 2,000degC for end use applications. It offers exceptional resistance to thermal shock, chemical corrosion and has excellent oxidation resistance as well as creep rupture strength.

High Temperature Resistance

Sintered silicon carbide stands up well to high temperatures while being resistant to corrosion, oxidation and impact shock, making it one of the world’s toughest materials. Able to withstand intense heat and pressure without cracking under strain, it makes an ideal material choice for blasting nozzles used in demanding environments like power plants or steel sintering plants.

SSiC can withstand temperatures of up to 1,900 degrees Celsius, well beyond most alloys’ melting points. Furthermore, it is highly resistant to chemical erosion and chemical impact; making it a suitable material for demanding applications like metal casting.

Sintered silicon carbide is produced using several ceramic forming processes, including extrusion (tubes) and cold isostatic pressing for plates and blocks. After being machined to precise tolerances, it’s then sintered in a controlled atmosphere to prevent oxidation and become strong, hard, and thermally conductible material. Although costly and time consuming, this production method produces top quality silicon carbide products boasting great strength, hardness and thermal conductivity properties.

Reaction bonded silicon carbide (RBSIC), on the other hand, falls short when it comes to flexural strength, chemical resistance and fracture toughness. Reaction bonded silicon carbide is formed by injecting liquid silicon into porous carbon or graphite preforms; its production costs are lower than for SSiC while smaller parts and complex shapes are easier to manufacture using it; its performance at high temperatures also outshone that of its rival material.

High Temperature Conductivity

Thermal conductivity of sintered silicon carbide increases as its additive content changes, due to an increase in liquid phase eutectic between SiC grains with increasing temperature causing its ceramic density to increase, leading to greater electrical conductivity through its insulating network.

SSiC boasts higher sintering temperatures that make it easier to machine and deliver tighter tolerances than reaction bonded silicon carbide (RBSIC), making it suitable for manufacturing process equipment components like nozzles, valves, shaft sleeves or kiln furniture.

Morgan’s Purebide(r) SSiC grade offers outstanding abrasion resistance with excellent chemical resistance and exceptional flexural strength at elevated temperatures. Furthermore, the addition of free graphite enhances lubricity for improved pressure velocity capability between hardface mating pairs.

Reaction bonded silicon carbide is created by infiltrating molten silicon into porous carbon or graphite preforms, then pressing and sintering them to produce reaction bonded silicon carbide (RBSC). Although its strength and hardness may fall below that of SSiC, reaction bonded SC provides excellent wear resistance while being much cheaper to produce – plus production times can often be quicker making this option an appealing solution for certain applications.

Pressureless sintered silicon carbide boasts the mechanical properties of a polycrystalline, face-centered cubic material with low expansion coefficient, making it suitable for precision applications like molds and wear parts. Furthermore, its extreme temperature durability shows excellent resistance against chemical attacks while offering thermal stability as an additional bonus.

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