SiC Mechanical Seal

Silicon carbide products are classified into many kinds according to different application environment. It is generally used more mechanically. For example, silicon carbide is an ideal material for silicon carbide mechanical seal because of its good chemical corrosion resistance, high strength, high hardness, good wear resistance, small friction coefficient and high temperature resistance.
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Silicon Carbide Seal Material

Silicon carbide (SiC) is also known as carborundum, which is made of quartz sand, petroleum coke (or coal coke), wood chips (which need to be added when producing green silicon carbide) and so on. Silicon carbide also has a rare mineral in nature, mulberry. In contemporary C, N, B and other non-oxide high technology refractory raw materials, silicon carbide is one of the most widely used and economical materials, which can be called gold steel sand or refractory sand. At present, China’s industrial production of silicon carbide is divided into black silicon carbide and green silicon carbide, both of which are hexagonal crystals with a proportion of 3.20 ~ 3.25 and microhardness of 2840 ~ 3320kg/mm2.

Types of Silicon Carbide Seal Rings

SiC Seal rings can be divided into static ring, moving ring, flat ring and so on. SiC silicon cab be made into various carbide products, such as silicon carbide, silicon carbide, silicon carbide ring and so on, according to the special requirements of customers. It can also be used in combination with graphite material, and its friction coefficient is smaller than alumina ceramic and hard alloy, so it can be used in high PV value, especially in the condition of strong acid and strong alkali.

Sic Seal Material Property

The following tables introduce R-SiC and S-SiC.
properties R-SiC S-SiC
Porosity (%) ≤0.3 ≤0.2
Density (g/cm3) 3.05 3.1~3.15
Hardness 110~125 (HS) 2800 (kg/mm2)
Elastic Modulus (Gpa) ≥400 ≥410
SiC Content (%) ≥85% ≥99%
Si Content (%) ≤15% 0.10%
Bend Strength (Mpa) ≥350 450
Compressive Strength (kg/mm2) ≥2200 3900
Coefficient of heat expansion (1/℃) 4.5×10-6 4.3×10-6
Heat resistance (in the atmosphere) (℃) 1300 1600

Test Environment Corrosive Weight Loss (mg/cm2yr)
Concentration Reagent (wt%) Temperature R-SIC S-SIC
(℃)
98%H2S04 100 50 1.5
50% NaOH 100 1000 2.5
53% HF 100 7 0.2
85% H3P04 100 8 0.2
70% HNO3 100 0.5 0.2
45% KOH 100 1000 0.2
25% HCL 100 0.9 0.2
10% HF plus 25 1000 0.2
57% HNO3

Test Environment: 125-300 hours of immerged testing, continuously stirred
 

Silicon Carbide Pump Seals