MAX ceramic bonded diamond composites were fabricated by microwave sintering from MAX phases and diamond raw powders.The effect of MAX phase and diamond content on phase and micro-structure of composites were studied.The result showed that different coating on the diamond could be obtained after microwave sintering.MAX phases'type and diamond had a different effect on the matrix composition and surface coating of diamond.Ti
2SnC might be obviously decomposed to Sn and TiC in the Ti
2SnC-diamond composites.When diamond content was lower,its surface was smoother.Additionally,small amount of circle organization were formed on the diamond.When diamond content was higher,many fine TiC grains were formed on the diamond.Ti
3AlC
2 may be also obviously decomposed to Al and TiC in the Ti
3AlC
2-diamond composites after sintering.Diamond was eroded obviously.Al
4C
3 and Al
2O
3 organization were formed on the surface of diamond.In Ti
3SiC
2-diamond system,the main phase of the matrix was Ti
3SiC
2.When diamond mass fraction was 10%,small amounts of Si,TiSi
2 and SiC were obtained.When diamond mass fraction was 20%,tiny TiC was obtained.SiC and TiSi
2 binary organization were formed on the diamond.