PHOSPHATE-BONDED GRINDING WHEEL

• US 3,770,401 A
• Filed: 04/05/1971
• Issued: 11/06/1973
• Est. Priority Date: 04/05/1971
• Status: Expired due to Term

• Current Assignee: Herbert D. Sheets Jr, Martin J O'Hara, Ronald A. Meyer
• Original Assignee: Herbert D. Sheets Jr, Martin J O'Hara, Ronald A. Meyer
• Inventors: Sheets, Herbert D. Jr., O'Hara, Martin J., Meyer, Ronald A.
• Primary Examiner(s): Arnold, Donald J.
• Application Number:
  US05/131,435
• Time in Patent Office: 946 Days
• Field of Search: 51/295,298,307,308,309
• US Class Current: 51/308
• CPC Class Codes: B24D 3/14 ceramic, i.e. vitrified bondings

Abstract

An abrasive body of grit-size particles of alumina or silicon carbide held together by a water-insoluble aluminum phosphate bonding matrix, which body is of increased strength through its phosphate bonding matrix containing a small amount of at least one or both of particlate aluminum and an in-situ formed phosphosilicate; and an improved molding composition for preparing the abrasive body, which molding composition contains up to 12 percent by weight thereof of particulate aluminum of minus 200 mesh size and/or sodium silicate having a SiO2 to Na2O weight ratio greater than 1 and less than 3.8.

Claims

2. The composition of claim 1 including the strength-promoting agent which is said particulate aluminum.

3. The composition of claim 1 including the strength-promoting agent which is said sodium silicate.

4. The composition of claim 1 including both said particulate aluminum and said sodium silicate as the strength-promoting agent.

5. An improved mixed cohesive molding composition for cold-pressing and subsequent heat-curing to become an article containing abrasive grit particles held together by a water-insoluble phosphate matrix, which composition for each 100 parts by weight thereof comprises:

a. between 4 and 2.5 parts by weight of at least one strength-promoting agent selected from the group consisting of particulate aluminum of less than 200 mesh size and sodium silicate having a SiO2 to Na2O weight ratio between 2.0 and 3.3;

b. from 62 to 78 parts by weight of abrasive-grit particles selected from the group consisting of alumina and silicon carbide;

c. from 11 to 6 parts by weight of phosphoric acid whose free water content constitutes less than 3 percent by weight of the composition;

d. from 25 to 15 parts by weight of -325 mesh alumina particles; and

e. from 2 to 1 parts by weight of less than 3 micron size ferric oxide particles.

6. The composition of claim 5 including the strength-promoting agent which is said particulate aluminum.

7. The composition of claim 5 including the strength-promoting agent which is said sodium silicate.

8. The composition of claim 5 including both said particulate aluminum and said sodium silicate as the strength-promoting agent.

9. An abrasive body comprised of:

a. abrasive grit particles selected from the group consisting of grit-size particles of alumina and silicon carbide in an amount constituting from 30 to 60 percent by volume of said body;

held together by b. a water-insoluble phosphate bonding matrix constituting at least 8 percent by volume of said body, which water-insoluble bonding matrix consists essentially of aluminum phosphates and a minor amount of iron phosphates intermingled therewith and includes a minor amount up to 10 percent by volume of at least one or of both of particulate aluminum of less than 200 mesh size and an in-situ formed phospho-silicate.

10. The body of claim 9 which contains the particulate aluminum.

11. The body of claim 9 which contains the phospho-silicate.

12. The body of claim 9 which contains both the particulate aluminum and the phospho-silicate.