The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform

P. Mayr - One of the best experts on this subject based on the ideXlab platform.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface & Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiN x ), which exhibits minor abrasive and Chemical Wear of diamond. But the crystallite size and hardness of those coatings still has to be lowered in order to be able to compete with the established NiP x coatings. Therefore, in this work copper is added to TiN x coatings to adjust their morphology and hardness. The coatings are deposited by means of reactive DC magnetron sputtering. The titanium to copper ratio and the nitrogen content of the coatings are varied. The Chemical composition is investigated by glow discharge optical spectroscopy. To evaluate the reactivity of diamond with the coating surface a contact test is performed in a vacuum chamber, where a monocrystalline diamond is pressed on the coating surface at a pressure of less than 0.1 mPa and a temperature of 800 °C. Scanning electron microscopy and energy dispersive X-ray analysis of the contact areas of the coating and the diamond provide information of the Chemical Wear of the diamond.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface and Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiNx

  • Deposition of alumina coatings on monocrystalline diamonds by sol-gel techniques
    Diamond and Related Materials, 2001
    Co-Authors: B. Felde, Ralf Gläbe, J. Kohlscheen, A. Mehner, F. Hoffmann, P. Mayr
    Abstract:

    Abstract Machining of steel or iron-based alloys with diamond tools leads to rapid tool failure — probably due to Chemical Wear. The use of monocrystalline diamond tools has, up to now, been obligatory for precision machining. Coating the diamonds with a thin but hard and Chemically inert alumina film may overcome the problem. Alumina coatings were deposited by sol–gel techniques. It was shown that a very thin TiN intermediate layer, deposited by reactive sputtering, results in a good adhesion of the alumina coatings to the monocrystalline diamonds. The microstructure of the coatings was characterized by field-emission scanning electron microscopy (FE-SEM) and by transmission electron microscopy (TEM). The deposited coatings showed a nanocrystalline, dense microstructure. The hardness of the coatings was investigated by ultramicrohardness measurements (UMH).

A. Vennemann - One of the best experts on this subject based on the ideXlab platform.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface & Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiN x ), which exhibits minor abrasive and Chemical Wear of diamond. But the crystallite size and hardness of those coatings still has to be lowered in order to be able to compete with the established NiP x coatings. Therefore, in this work copper is added to TiN x coatings to adjust their morphology and hardness. The coatings are deposited by means of reactive DC magnetron sputtering. The titanium to copper ratio and the nitrogen content of the coatings are varied. The Chemical composition is investigated by glow discharge optical spectroscopy. To evaluate the reactivity of diamond with the coating surface a contact test is performed in a vacuum chamber, where a monocrystalline diamond is pressed on the coating surface at a pressure of less than 0.1 mPa and a temperature of 800 °C. Scanning electron microscopy and energy dispersive X-ray analysis of the contact areas of the coating and the diamond provide information of the Chemical Wear of the diamond.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface and Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiNx

J. Kohlscheen - One of the best experts on this subject based on the ideXlab platform.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface & Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiN x ), which exhibits minor abrasive and Chemical Wear of diamond. But the crystallite size and hardness of those coatings still has to be lowered in order to be able to compete with the established NiP x coatings. Therefore, in this work copper is added to TiN x coatings to adjust their morphology and hardness. The coatings are deposited by means of reactive DC magnetron sputtering. The titanium to copper ratio and the nitrogen content of the coatings are varied. The Chemical composition is investigated by glow discharge optical spectroscopy. To evaluate the reactivity of diamond with the coating surface a contact test is performed in a vacuum chamber, where a monocrystalline diamond is pressed on the coating surface at a pressure of less than 0.1 mPa and a temperature of 800 °C. Scanning electron microscopy and energy dispersive X-ray analysis of the contact areas of the coating and the diamond provide information of the Chemical Wear of the diamond.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface and Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiNx

  • Deposition of alumina coatings on monocrystalline diamonds by sol-gel techniques
    Diamond and Related Materials, 2001
    Co-Authors: B. Felde, Ralf Gläbe, J. Kohlscheen, A. Mehner, F. Hoffmann, P. Mayr
    Abstract:

    Abstract Machining of steel or iron-based alloys with diamond tools leads to rapid tool failure — probably due to Chemical Wear. The use of monocrystalline diamond tools has, up to now, been obligatory for precision machining. Coating the diamonds with a thin but hard and Chemically inert alumina film may overcome the problem. Alumina coatings were deposited by sol–gel techniques. It was shown that a very thin TiN intermediate layer, deposited by reactive sputtering, results in a good adhesion of the alumina coatings to the monocrystalline diamonds. The microstructure of the coatings was characterized by field-emission scanning electron microscopy (FE-SEM) and by transmission electron microscopy (TEM). The deposited coatings showed a nanocrystalline, dense microstructure. The hardness of the coatings was investigated by ultramicrohardness measurements (UMH).

Kanako Obata - One of the best experts on this subject based on the ideXlab platform.

  • Thermo-Chemical Wear mechanism of diamond tool in machining of ferrous metals
    CIRP Annals - Manufacturing Technology, 2004
    Co-Authors: S Shimada, Sawao Honda, H. Tanaka, T. Yamaguchi, M. Higuchi, Kanako Obata
    Abstract:

    To understand the Wear mechanism of diamond tool in machining of ferrous metals, an erosion test simulating Wear process and ab-initio molecular orbital calculation are carried out. The results of the tests and analyses show that the essential Wear mechanism at the temperature higher than 1000K is the dissociation of carbon atoms on diamond surface due to the interaction with iron surface. The Wear rate is controlled by the removal rate of dissociated carbon atoms from the tool-work interface such as diffusion into workpiece. At the temperature lower than 900K, the mechanism involves the removal of carbon atoms due to oxidization of diamond accompanied with deoxidization of iron oxide.

E. Vorgel - One of the best experts on this subject based on the ideXlab platform.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface & Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiN x ), which exhibits minor abrasive and Chemical Wear of diamond. But the crystallite size and hardness of those coatings still has to be lowered in order to be able to compete with the established NiP x coatings. Therefore, in this work copper is added to TiN x coatings to adjust their morphology and hardness. The coatings are deposited by means of reactive DC magnetron sputtering. The titanium to copper ratio and the nitrogen content of the coatings are varied. The Chemical composition is investigated by glow discharge optical spectroscopy. To evaluate the reactivity of diamond with the coating surface a contact test is performed in a vacuum chamber, where a monocrystalline diamond is pressed on the coating surface at a pressure of less than 0.1 mPa and a temperature of 800 °C. Scanning electron microscopy and energy dispersive X-ray analysis of the contact areas of the coating and the diamond provide information of the Chemical Wear of the diamond.

  • New diamond turnable coatings of ternary systems for ultraprecision cutting
    Surface and Coatings Technology, 2003
    Co-Authors: A. Vennemann, J. Kohlscheen, H.-r. Stock, E. Vorgel, P. Mayr
    Abstract:

    Abstract Moulding tools for optical components need optical surface quality. To reach this high quality surface the machining with monocrystalline diamond tools is most suitable. Steels which are used as materials for moulding tools are not diamond machinable due to heavy Chemical Wear of the diamond tool. Therefore diamond machinable coatings have to be deposited on the moulding tools before final cutting. Up to now electroless nickel phosphorus coatings are the only diamond turnable coatings, but their hardness and temperature stability is limited. For this reason new diamond machinable coatings with higher hardness and improved temperature stability have to be developed. One promising coating is substoichiometric titanium nitride (TiNx