Bonding structure and bonding method for cemented carbide element and diamond element, cutting tip and cutting element for drilling tool, and drilling tool

A method of producing a cutting tip, comprising:

• fabricating a cemented carbide cutting base having a predetermined shape;
• fabricating a diamond element by processing a sintered diamond into a predetermined shape;
• interposing a metal material including one or two or more metals selected from a group consisting of Fe, Ni, Co, Ti, Zr, W, V, Nb, Ta, Cr, Mo, and Hf between the cemented carbide cutting base and the diamond element;
• and
• performing bonding of said cemented carbide cutting base and said diamond element comprising the steps of:
• heating said cemented carbide cutting base, said diamond element, and said metal material;
• forming a diffusion layer in which said metal diffuses into at least one of said cemented carbide cutting base or said diamond element;
• and
• bonding said cemented carbide cutting base and said diamond element,
• wherein said heating is carried out under conditions A (K) and B(GPa) that satisfy the following two equations simultaneously:
• A>1175
• B>0.0027×A+0.81,
• such that the maximum content of said metals in said diffusion layer of said cemented carbide cutting base is 20 times or greater than the average content of said metals outside the diffusion layer, and 100 times or greater than an average content of said metals in said diamond element than an average content outside the diffusion layer, wherein the measurement is in a cross-section in a transverse direction of said diffusion layer and is made by line analysis using EPMA.