Laser-Interference Surface Preparation for Enhanced Coating Adhesion and Adhesive Joining of Multi-Materials

The plasma-assisted chemical vapor deposition (PACVD) technique has shown many advantages in applications, where thin coatings with superior wear properties are demanded, especially for geometrically complex parts. In this study, multilayered gradient TiBN coatings that were deposited on nanostructured cemented carbides by the PACVD method were investigated. Nanostructured samples of cemented carbides with the addition of 5 and 15 wt.% Co were sintered by the hot isostatic pressing, sinter-HIP technique. Surface preparation was conducted on samples in order to enable maximum coating adhesion. Tests that were conducted on produced samples aimed to investigate the mechanical and physical properties of coated samples. These tests included nanoindentation, surface layer characterization, and coating adhesion evaluation while using the Rockwell and scratch test. The obtained results confirmed that the PACVD process can be utilized for applying thin hard coatings to nanostructured cemented carbides that are produced by the sinter HIP process, resulting in a base material/ coating system that exhibits excellent physical and mechanical properties. The results presented in this paper give a valuable contribution to the research of TiBN coating systems and their potential for application under heavy wear conditions.

Download Full-text

Influence of part surface preparation on the coating adhesion strength of during plasma spraying

NOVYE OGNEUPORY (NEW REFRACTORIES) ◽

10.17073/1683-4518-2021-3-40-47 ◽

2021 ◽

Vol 1 (3) ◽

pp. 40-47

Author(s):

I. N. Kravchenko ◽

S. V. Kartsev ◽

S. A. Velichko ◽

Yu. A. Kuznetsov ◽

A. G. Pastukhov

Keyword(s):

Plasma Spraying ◽

Adhesion Strength ◽

Surface Preparation ◽

Coating Adhesion ◽

Part Surface

.

Download Full-text

Coating adhesion of a chromate-containing epoxy primer on Al2024-T3 surface processed by laser-interference

International Journal of Adhesion and Adhesives ◽

10.1016/j.ijadhadh.2020.102641 ◽

2020 ◽

Vol 102 ◽

pp. 102641

Author(s):

Adrian S. Sabau ◽

Jiheon Jun ◽

Dana McClurg

Keyword(s):

Laser Interference ◽

Coating Adhesion ◽

Epoxy Primer

Download Full-text

Adhesive Bonding of Copper Prepared by Laser-Interference near the Interference Structuring Limits

Materials ◽

10.3390/ma14133485 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3485

Author(s):

Haotian Liu ◽

Justin A. Weibel ◽

Eckhard A. Groll ◽

Adrian S. Sabau ◽

Patrick Geoghegan ◽

...

Keyword(s):

Adhesive Bonding ◽

Surface Preparation ◽

Maximum Load ◽

Processing Parameters ◽

Spot Size ◽

Surface Topology ◽

Laser Interference ◽

Bonding Performance ◽

Lap Shear ◽

Joint Quality

Adhesive bonding requires adequate surface preparation for ensuring an appropriate joint quality. The interest in adhesive joining has recently expanded to thermal systems having a large number of joints employed for manufacturing and assembly. This study presents surface topology of copper 110 produced by a laser-interference setup that would theoretically yield a periodicity of 1.7 μm, which is near the 1.6–2 μm structuring limit that was estimated based on thermal diffusion length scale for an 8 ns laser pulse. The results show that although the expected periodic interference structuring was not attained, the melt-induced texturing was affected by the laser-interference profile. Single-lap shear tests were performed with specimen surfaces prepared by traditional abrasion and laser-interference structuring methods. Several laser processing parameters, such as the laser spot size, density, number of pulses, and raster speed, were studied. Scanning electron microscope and profilometry measurements were used to characterize the processed surface microstructures. Web-like structures, which indicate widespread melting, were shown to be formed at different processing conditions. Based on the surface topologies investigated, two laser raster speeds were selected to make single-lap-joint specimens. Baseline joints were prepared by abrading joining specimens. The shear-lap strength and displacement at maximum load were shown to be higher by 16.8% and 43.8% for the laser-structured specimens than those of the baseline specimens, respectively. Moreover, the load-displacement curves indicated that the laser-structured joints were more ductile than those without laser-structuring. The increased ductility for the laser-structured joints was found to yield an increase in the energy absorbed during shear-lap testing of approximately of 80–90% over those measured for baseline joints. It is another indicator that laser-interference structuring enhanced the bonding performance of single-lap shear joints.

Download Full-text

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139068 ◽

1995 ◽

Vol 53 ◽

pp. 538-539

Author(s):

E Y. Wang ◽

J. T. Cherian ◽

A. Madsen ◽

R. M. Fisher

Keyword(s):

Steel Surface ◽

Surface Preparation ◽

Treatment Method ◽

Chrome Plating ◽

Transmission Electron ◽

Alloy Steels ◽

Pre Treatment ◽

Hard Chrome ◽

Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

Download Full-text

Selective Corrosion of brazed joint between BNi-2 filler metal and stainless steel 316

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163551 ◽

1996 ◽

Vol 54 ◽

pp. 218-219

Author(s):

H. S. Kim ◽

R. U. Lee

Keyword(s):

Stainless Steel ◽

Filler Metal ◽

Surface Preparation ◽

Optical Microscope ◽

Heating Element ◽

Incomplete Fusion ◽

Atmospheric Conditions ◽

Leak Test ◽

High Temperature Side ◽

Inconel 600

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.

Download Full-text