full ceramic bearings | Silicon Nitride Ceramic Bearings

Ceramic bearings in Si3N4 for shaft sizes from 3mm up to 50mm
See product table below for dimensions and technical drawings
See Products Variants below for ZrO2 options

Si3N4, or silicon nitride, is a very hard but also very light ceramic material. Si3N4 has excellent resistance to water, salt water and many acids and alkalis. It also has a very wide temperature range and is suitable for use in high vacuum applications. The extreme hardness of silicon nitride also means greater brittleness so shock/impact loads should be minimised to avoid the risk of cracking. A silicon nitride bearing is only 40% of the weight of its steel equivalent.

Unlike zirconia, silicon nitride has a low coefficient of expansion so care should be exercised when choosing shaft fits for higher temperature applications as a steel shaft will expand much more than the silicon nitride inner ring which could lead to ring fracture. In the same way, a steel housing will expand much more than a silicon nitride outer ring, leading to a looser fit at high temperatures.

The Si3N4 full ceramic ball bearings in the table below are available with cages (or retainers) made from PEEK, PTFE or 316 stainless steel. In addition, we keep stock of full complement silicon nitride bearings. These have no cage and extra balls. For the bearings with cages, PEEK cages are generally the option available from stock due to the strength and durability of PEEK. If an alternative cage material is required to cope with particular chemicals or temperature extremes beyond the range of PEEK, these can be produced to order. Si3N4 bearings are not magnetic and they are highly corrosion resistant to most chemicals. They are also electrically insulating. Like ZrO2 bearings, they are also extremely water resistant which is why they are often used in marine applications. They can be fully and permanently submerged without the material being affected. Due to their greater brittleness, Si3N4 bearings have slightly lower load ratings than ZrO2 bearings but will still cope with much higher loads and speeds than 316 marine grade bearings. 

Full complement Si3N4 bearings can be used up to 800°C. Bearings with a PEEK cage are rated up to only 250°C while silicon nitride bearings with a 316 stainless steel cage can be used up to 500°C. Although silicon nitride expands much less than ZrO2, it is still advisable to specify greater internal clearance at high temperatures to avoid problems caused by radial play reduction. Our silicon nitride bearings are supplied with a C3 loose radial play as standard.

For temperatures below -70°C it is worth considering PTFE or 316 stainless steel cages due to their better low temperature performance. For an overview of the pros and cons of silicon nitride bearings, you can click HERE to see our ceramic bearing selection guide. 

Most of the range of Si3N4 ceramic bearings are supplied from stock in the UK. We also keep ZrO2 full ceramic bearings in stock. See Products Variants below for the ZrO2 versions.

Click on INFO in the rows below to display technical drawings of the bearings with load and speed data. Please note that the maximum loads and speeds are used in theoretical life calculations. It is recommended to use bearings at significantly less than the maximum load and speed ratings to ensure reasonable bearing life. Si3N4 full ceramic bearings are best used with low to medium speeds and loads due to their greater brittleness.

 

Products Variants
ceramic bearings | ceramic bearings uk | zirconia ceramic bearings

Full Ceramic Bearings in ZrO2

ZrO2

More Information

Product Details Si3N4

BORE

(mm)

O.D.

(mm)

WIDTH

(mm)

SMB REFERENCE

(Open Bearings)

DRAWINGS

SMB REFERENCE

(Sealed Bearings)

DRAWINGS

3

8

3

CCSI-693

info

 

 

8

4

 

 

CCSI-693-2PKS

info

9

3

CCSI-603

info

 

 

9

5

 

 

CCSI-603-2PKS

info

10

4

CCSI-623

info

CCSI-623-2PKS

info

4

9

2.5

CCSI-684

info

 

 

9

4

 

 

CCSI-684-2PKS

info

11

4

CCSI-694

info

CCSI-694-2PKS

info

12

4

CCSI-604

info

CCSI-604-2PKS

info

13

5

CCSI-624

info

CCSI-624-2PKS

info

16

5

CCSI-634

info

CCSI-634-2PKS

info

5

11

3

CCSI-685

info

 

 

11

5

 

 

CCSI-685-2PKS

info

13

4

CCSI-695

info

CCSI-695-2PKS

info

14

5

CCSI-605

info

CCSI-605-2PKS

info

16

5

CCSI-625

info

CCSI-625-2PKS

info

19

6

CCSI-635

info

CCSI-635-2PKS

info

6

13

3.5

CCSI-686

info

 

 

13

5

 

 

CCSI-686-2PKS

info

15

5

CCSI-696

info

CCSI-696-2PKS

info

17

6

CCSI-606

info

CCSI-606-2PKS

info

19

6

CCSI-626

info

CCSI-626-2PKS

info

22

7

CCSI-636

info

CCSI-636-2PKS

info

7

14

3.5

CCSI-687

info

 

 

14

5

 

 

CCSI-687-2PKS

info

17

5

CCSI-697

info

CCSI-697-2PKS

info

19

6

CCSI-607

info

CCSI-607-2PKS

info

22

7

CCSI-627

info

CCSI-627-2PKS

info

26

9

CCSI-637

info

CCSI-637-2PKS

info

8

16

4

CCSI-688

info

 

 

16

5

 

 

CCSI-688-2PKS

info

19

6

CCSI-698

info

CCSI-698-2PKS

info

22

7

CCSI-608

info

CCSI-608-2PKS

info

24

8

CCSI-628

info

CCSI-628-2PKS

info

28

9

CCSI-638

info

CCSI-638-2PKS

info

9

17

4

CCSI-689

info

 

 

17

5

 

 

CCSI-689-2PKS

info

20

6

CCSI-699

info

CCSI-699-2PKS

info

24

7

CCSI-609

info

CCSI-609-2PKS

info

26

8

CCSI-629

info

CCSI-629-2PKS

info

30

10

CCSI-639

info

CCSI-639-2PKS

info

10

15

3

CCSI-6700

info

 

 

15

4

 

 

CCSI-6700-2PKS

info

19

5

CCSI-6800

info

CCSI-6800-2PKS

info

22

6

CCSI-6900

info

CCSI-6900-2PKS

info

26

8

CCSI-6000

info

CCSI-6000-2PKS

info

30

9

CCSI-6200

info

CCSI-6200-2PKS

info

35

11

CCSI-6300

info

CCSI-6300-2PKS

info

12

18

4

CCSI-6701

info

CCSI-6701-2PKS

info

21

5

CCSI-6801

info

CCSI-6801-2PKS

info

24

6

CCSI-6901

info

CCSI-6901-2PKS

info

28

8

CCSI-6001

info

CCSI-6001-2PKS

info

32

10

CCSI-6201

info

CCSI-6201-2PKS

info

37

12

CCSI-6301

info

CCSI-6301-2PKS

info

15

21

4

CCSI-6702

info

CCSI-6702-2PKS

info

24

5

CCSI-6802

info

CCSI-6802-2PKS

info

28

7

CCSI-6902

info

CCSI-6902-2PKS

info

32

9

CCSI-6002

info

CCSI-6002-2PKS

info

35

11

CCSI-6202

info

CCSI-6202-2PKS

info

42

13

CCSI-6302

info

CCSI-6302-2PKS

info

17

23

4

CCSI-6703

info

CCSI-6703-2PKS

info

26

5

CCSI-6803

info

CCSI-6803-2PKS

info

30

7

CCSI-6903

info

CCSI-6903-2PKS

info

35

10

CCSI-6003

info

CCSI-6003-2PKS

info

40

12

CCSI-6203

info

CCSI-6203-2PKS

info

47

14

CCSI-6303

info

CCSI-6303-2PKS

info

20

27

4

CCSI-6704

info

CCSI-6704-2PKS

info

32

7

CCSI-6804

info

CCSI-6804-2PKS

info

37

9

CCSI-6904

info

CCSI-6904-2PKS

info

42

12

CCSI-6004

info

CCSI-6004-2PKS

info

47

14

CCSI-6204

info

CCSI-6204-2PKS

info

52

15

CCSI-6304

info

CCSI-6304-2PKS

info

25

32

4

CCSI-6705

info

CCSI-6705-2PKS

info

37

7

CCSI-6805

info

CCSI-6805-2PKS

info

42

9

CCSI-6905

info

CCSI-6905-2PKS

info

47

12

CCSI-6005

info

CCSI-6005-2PKS

info

52

15

CCSI-6205

info

CCSI-6205-2PKS

info

62

17

CCSI-6305

info

CCSI-6305-2PKS

info

30

37

4

CCSI-6706

info

CCSI-6706-2PKS

info

42

7

CCSI-6806

info

CCSI-6806-2PKS

info

47

9

CCSI-6906

info

CCSI-6906-2PKS

info

55

13

CCSI-6006

info

CCSI-6006-2PKS

info

62

16

CCSI-6206

info

CCSI-6206-2PKS

info

72

19

CCSI-6306

info

CCSI-6306-2PKS

info

35

44

5

CCSI-6707

info

CCSI-6707-2PKS

info

47

7

CCSI-6807

info

CCSI-6807-2PKS

info

55

10

CCSI-6907

info

CCSI-6907-2PKS

info

62

14

CCSI-6007

info

CCSI-6007-2PKS

info

72

17

CCSI-6207

info

CCSI-6207-2PKS

info

80

21

CCSI-6307

info

CCSI-6307-2PKS

info

40

50

6

CCSI-6708

info

CCSI-6708-2PKS

info

52

7

CCSI-6808

info

CCSI-6808-2PKS

info

62

12

CCSI-6908

info

CCSI-6908-2PKS

info

68

15

CCSI-6008

info

CCSI-6008-2PKS

info

80

18

CCSI-6208

info

CCSI-6208-2PKS

info

90

23

CCSI-6308

info

CCSI-6308-2PKS

info

45

55

6

CCSI-6709

info

CCSI-6709-2PKS

info

58

7

CCSI-6809

info

CCSI-6809-2PKS

info

68

12

CCSI-6909

info

CCSI-6909-2PKS

info

75

16

CCSI-6009

info

CCSI-6009-2PKS

info

85

19

CCSI-6209

info

CCSI-6209-2PKS

info

100

25

CCSI-6309

info

CCSI-6309-2PKS

info

50

62

6

CCSI-6710

info

CCSI-6710-2PKS

info

65

7

CCSI-6810

info

CCSI-6810-2PKS

info

72

12

CCSI-6910

info

CCSI-6910-2PKS

info

80

16

CCSI-6010

info

CCSI-6010-2PKS

info

90

20

CCSI-6210

info

CCSI-6210-2PKS

info

110

27

CCSI-6310

info

CCSI-6310-2PKS

info

Our determination to remain specialised gives us a high level of product knowledge, providing bearing and lubrication solutions to existing or potential customers, whether individuals or large corporations. We don’t just sell bearings, we help to solve your problems. - Chris Johnson, managing director of SMB Bearings.