Products and Service

1. Polycrystalline Diamond (PCD)

PCD

We can provide a wide range of polycrystalline diamond (PCD) products to meet the demands of the precision cutting, oil & gas and hardrock mining industries.

PCD consists of micron-sized synthetic diamond powders bonded together by sintering at high pressures and temperatures. PCD is produced on a cemented carbide substrate, so as to provide a source of ‘solvent metal catalyst’ to aide sintering, typically cobalt. Under extreme pressures and temperatures, the cobalt from the cemented carbide substrate infiltrates through the layer of micron synthetic diamond powder, causing neighbouring grains to 

grow together. Not only does the small residue of cobalt provide significant toughening, it also renders the material electrically conductive.As such, PCD may be electric-discharge machined – a critical attribute for the hardest known material. The integrally bonded carbide substrate also renders the composite brazeable, another critical attribute given that the major part of a cutting tool or drill bit is used solely for clamping, with the PCD material only located where it is used for cutting.

Every tool material must combine sufficient toughness with wear resistance. However, features with increased toughness will invariably have lower wear resistance. As a result, materials must be engineered to meet the demands of specific applications. In the case of PCD, the properties of the composite are engineered partly by modifying the size of the constituent synthetic diamond grains. As the grain size increases, so too does the wear resistance, albeit at the expense of strength. By reducing the grain size to one micron or less, the wear resistance and strength may both be increased beyond what is possible with slightly coarser materials and this. Finer grain size materials are easier to mechanically grind and electric-discharge machine, and also provide a better workpiece surface finish in precision machining applications. Now we can make fine grain size PCD (2 micron, 1 micron, and sub-micron), which exhibits the highest wear resistance but due to a proprietary coarse-to-fine multi-modal grain size distribution, does not present the drawbacks of conventional coarse grain materials.

2. Polycrystalline Diamond Compact (PDC)

PDC
Polycrystalline diamond cutters (also known as polycrystalline diamond compacts or PDC) for use in oil & gas drill bits. This products offers the widest possible drilling solutions to meet the challenging requirements of oil & gas exploration and production.

Polycrystalline diamond cutters (PDC) comprise a polycrystalline diamond (PCD) top layer integrally sintered onto a tungsten carbide substrate using a high-pressure, high-temperature process. This layer combination allows consistently high drilling performance to be maintained. The polycrystalline diamond layer offers controlled wear and the retention of a sharp cutting edge. The tungsten carbide substrate provides a strong and tough support for the polycrystalline diamond layer while facilitating attachment to the drill bit body.

3. Polycrystalline cubic boron nitride (PCBN)

Polycrystalline cubic boron nitride (PCBN) composites are produced by sintering micron CBN (cubic boron nitride) powders with various ceramics, so as to produce extremely hard and thermally stable tooling materials. Most PCBN materials are integrally bonded to a cemented carbide substrate. CBN is the second hardest material known after synthetic diamond, but has high thermal and chemical resistance properties. PCBN composites provide extreme resistance to deformation and wear at high temperatures – typically an order of magnitude better than the nearest ceramic materials.

About two thirds of all PCBN tools are used for the machining of hardened steels, offering a viable, more cost effective alternative to conventional grinding processes. Other applications are in the machining of hard, grey and high-strength cast iron, and cold and hot-work tool steels. The machining of nickel and cobalt-based superalloys is a significant and rapidly growing application area for PCBN.

We can provide PCBN products range from material with low to high CBN content. The chemical composition and microstructure greatly depending on the application. Lower CBN content materials tend to be more resistant to chemical wear mechanisms prevalent when continuously turning hardened steels. Where there are interrupts in the workpiece – oil-holes in a shaft, for example – a medium content grade is preferred, as it offers the best combination of wear resistance and toughness.

For applications where abrasion resistance is dominant, as in the machining of grey and hard cast irons, the high CBN grade (90) is the preferred choice. The high CBN grade also exhibits excellent thermal properties, and being available as solid (unbacked) materials, provides additional economic benefits. The high CBN grade is the workhorse grade for the roughing and finishing of brake discs and cast iron engine blocks, and typically outlasts ceramic tools by more than an order of magnitude, whilst operating at cutting speeds in excess of 2500 m/min.

4. Electrodeposited Diamond Wire Saw 

EDWS
Wire sawing is a process of cutting or grinding a silicon ingot, a sapphire wafer, and the like using a wire or a wire saw formed by forming a plurality of diamond grits on the wire. The wire may be formed of high tensile strength metals, such as a steel wire, nickel wire, nichrome wire, and the like, and other materials may also be used.The electrodeposited diamond wire saw is manufactured by electrodepositing diamond grits on an outer circumference of the wire in a longitudinal direction thereof. However, since electrodeposition of the diamond grits in a desired pattern on the wire is difficult in manufacture of the wire saw, it is difficult to achieve process efficiency and uniform quality in mass production.Thus, manufacturing costs of electrodeposited diamond wire saw are high and the process is labor intensive. Therefore, manufacturers have continually strived to develop methods of manufacturing electrodeposited diamond wire saws with improved process efficiency while reducing manufacturing costs.

Now, we can make the Ring Electrodeposited Diamond Wire Saw.

EDWS1
EDWS2

 

5. Patents

Xinyu Zhang, Jiaqian Qin, Yanan Xue, Mingzhen Ma, Riping Liu, Methods for low temperature synthesis of TiN-AlN-TiB2 composites. Patent No.: CN 104446499 B, 2016.5.4.

Xinyu Zhang, Jiaqian Qin, Mingzhen Ma, Riping Liu, Method of preparation of carbon-doped ZnO nanoparticles, Patent No.: CN 104445372 B, 2016.3.2.

Xinyu Zhang, Jiaqian Qin, Mingzhen Ma, Riping Liu, Methods for high hardness of NiW-diamond composite coatings, China Patent pending, No. 201410508115.1, 28 September 2014.

Xinyu Zhang, Jiaqian Qin, Mingzheng Ma, Riping Liu Method of preparation of carbon-doped ZnO nanorod, Patent No.: CN 104192890 B, Jan 6, 2016.

Zhao Wang, Duanwei He, Wei Zhang, Wenqiang Li, Wenyong Li, Li Lei, Jiaqian Qin, Yang Cao, Guan Li, “Protable high-pressure and gas hydrate experimental device”, Patent No.: CN 101458245

Recent Posts

PhD and Post-doc positions at Chulalongkorn University, Thailand

 •Opening for graduate students Open positions for Qin’s research group at Chulalongkorn University

Those who have strong interest and continuous curiosity in fundamental materials science are highly encouraged to apply. We prefer to recruit graduate students with following background:

• Solid background in materials science, materials physics, materials engineering, Physics, Chemistry, or Metallurgy

• Ready to sustain challenges in learning difficult subjects

• Opening for graduate students, senior project students, and visiting students

 Currently we have several openings for graduate students in the area of mechanical behavior of nanocomposite coatings; Nano photocatalyst; and supercapacitor. Please send your CV and unofficial transcripts to Dr. Qin directly (jiaqian.q@chula.ac.th).

• Postdoc

Please send your CV and unofficial transcripts to Dr. Qin directly (jiaqian.q@chula.ac.th).

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