Thermal Analysis of FeCoCu Pre-Alloyed Powders Used for Diamond Tools

Abstract

Thermal analysis of FeCoCu pre-alloyed powders used for diamond tools By simulating the pressureless sintering process, the thermal effects of FeCoCu pre-alloyed powders have been investigated. According to the notions of the Kissinger method, the activation energies in the expansion-shrinkage conversion stage are analyzed. Results show that with Fe content increasing, the specimens' specific heat capacity values present the increasing trend. The 25 %Fe-15 %Co-60 %Cu specimens have negative enthalpy value at 10 and 20°C/min heating rate but positive values at 30 °С/min. For the specimens with lower Cu content, the enthalpies are always positive. It is established that both the specific heat capacity and enthalpy are larger when at higher heating rates. The activation energy of the 65 %Fe-15 %Co-20 %Cu specimens is 10 times higher than that of the 25 %Fe-15 %Co-60 %Cu specimens and the 45 %Fe-15 %Co-40 %Cu specimens.

Effect of Deep Cryogenic Treatment on Microstructure and Properties of Sintered Fe–Co–Cu-Based Diamond Composites

“…The diamond grits (20 vol% concentration, synthetic, 270-380 µm, Zhengzhou, China) were added into the Fe-Co-Cu pre-alloy powder for preparing diamond composite samples through a three-axle mixer for 4 h. The samples (size: 38 × 8 × 5 mm 3 ) were sintered by hot-pressing in graphite molds at 840 • C and a pressure of 20 MPa for 4 min. Sintering temperature, pressure, and time were selected on the basis of previous research and published literature [4,9,10]. The composition, deep cryogenic treatment process, and mechanical properties of samples are given in Table 2.…”

“…At present, pre-alloyed powders have successfully realized industrial application in diamond tools, including diamond cutting segments and diamond drill bits [9][10][11][12]. The component uniformity is one of the advantages of pre-alloyed powders, because each alloying particle includes the entire composition, which means the segregation can be avoided [13].…”

“…In addition, the pre-alloying of powders can decrease the activation energy, which is conductive to reducing the sintering temperature, which in turn can avoid diamond graphitization [14]. The Fe-Co-Cu matrix, sintered from pre-alloyed Fe-Co-Cu powders, is usually used as the matrix in diamond tool manufacturing [4,10]. It has high strength and adjustable properties suitable for different kinds of hard materials, ensuring that the diamond grits contact the hard materials effectively, maintaining an abrasive cutting surface.…”

Effects of Sintering Parameters and WC Addition on Properties of Iron-Nickel Pre-Alloy Matrix Diamond Composites

“…At present, the main preparation methods of the pre-alloyed powders are water atomization method [11], hydrometallurgical co-precipitation method [12] and mechanical alloying method [13]. The study of pre-alloyed powders for diamond composites focus on the Fe-Co-Cu pre-alloyed powders [14][15][16][17][18]. To our best knowledge, there is no report about the impregnated diamond composites with iron-nickel pre-alloyed based matrix.…”