China Sealcon Company

SiC Mechanical Seal

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.

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

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%

0.1%

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

57% HNO3

25

1000

0.2


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

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