“…Various buffer interlayers including boron, [29] boron carbide, [30] b-SiC, [31] AlN, [32] B-C-N gradient layer, [33] B-rich BN layer, [34,35] tensile BN buffer layer, [36] and Zr-rich composite layer [37] have been incorporated to overcome these problems. Very recent experiments have shown that strongly-adherent cBN can grow on diamond directly and epitaxially without the aBN/tBN interfacial layer and the nucleation stage.…”