Indentation test using a cylindrical indenter with a flat end is now known as impression test. The advantage is its capability to reach a steady state for creep test at constant load and it is possible to compare with the conventional tensile or compression tests. The test is simple and all the temperature and strain rate dependences can be obtained locally from one sample avoiding the sample to sample variations. It became very popular in the last decade. The literature is reviewed here.

Impression test—A review

Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.

Electroless Ni-Co-P Coating of Cenospheres Using Ag(NH_3)_2~+ Activator

Preparation of Co-plated WC powders by a non-precious-Co-activation triggered electroless plating strategy

The influence of TiB2 content on microstructure and properties of W–30Cu composites prepared by electroless plating and powder metallurgy

The Ni-Co coated W-type barium ferrite (BaZn0.6Co1.4Fe16O27) hollow microspheres (W-BFHMs) have been prepared by the self-reaction quenching technology and heat treatment at 1250 ℃. The W-BFHMs is a type of light microwave absorbing material in GHz frequencies and its average particle size is 60 μm. A conductive and magnetic Ni-Co layer was coated on the surface of W-BFHMs by electroless plating. Effects of plating time on the particle size, morphology, phase structure and microwave absorption properties of Ni-Co coated W-BFHMs are investigated through SEM, XRD, particle size analyzer and vector network analyzer. The results show that the Ni-Co deposits in the sag and the trench firstly and grows as the branch after filling the sag and the trench. With the increase of the plating time from 5 min to 25 min, the magnetic loss increase from 0.15 to 0.35, while the dielectric loss is not significantly change due to the incompletely covered. The effective absorbing bandwidth increase from 1 GHz to 2.7 GHz, while the absorption peak decrease from -12 dB to -32dB when the plating time is 25 min.

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Zhang Run

Papers

Hollow Ceramic Microsphere Coated with Co by Electroless Plating and Its Electromagnetic Properties