A systematic study on the effect of coating type and surface preparation on the wettability of Si-Bronze brazing filler material on GI and GA-coated DP600

The brazeability of automotive zinc-coated steels depends on several factors. These include the morphology of the joint and the welding parameters selected. However, more fundamental material factors such as the composition of the coating, method of coating and coating thickness also have a significant effect. In this study, five commercially available and widely used automotive zinc-coated steels are investigated to assess brazeability. Surface zinc content and the coating type are shown to have a marked effect on the quality of the resulting joint. This is shown by surface analysis of the joint to determine evenness and bridging capability of the filler material and a cross-sectional analysis of the joints. Differences in wettability and contact length of the filler material and zinc-coated steel substrate are observed. It was found that electro-galvanised steel exhibited the best brazeability of the materials investigated here. Wettability of spreading angles as low as 17.3°, most uniform contact length and best bridging capability due to the filler material forming a metallic bond with the substrate were observed. However, pores were present in cross-sections. Galvannealed steel also showed good wetting with no embedded defects. Other steels used (galvanised and magnesium–aluminium zinc steels) presented problems with uniformity, high spreading angles of the filler material and poor bridging characteristics.

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Junction and Profile Analysis using Carrier Illumination

MRS Proceedings ◽

10.1557/proc-717-c7.3 ◽

2002 ◽

Vol 717 ◽

Cited By ~ 1

Author(s):

T. Clarysse ◽

W. Vandervorst ◽

R. Lindsay ◽

P. Borden ◽

E. Budiarto ◽

...

Keyword(s):

Quantitative Analysis ◽

Systematic Study ◽

Quantitative Measurement ◽

Concentration Level ◽

Profile Analysis ◽

Surface Preparation ◽

Optical Technique ◽

Junction Depth ◽

Cvd Growth ◽

Non Destructive

AbstractCarrier Illumination™ (CI) is an optical technique for non-destructive in-line monitoring of post-anneal junction depth and pre-anneal PAI depth and dose with wafer mapping capabilities. This work intends to extend the use of the CI-measurements from a range-specific quantitative measurement towards a more universal quantitative analysis of junction depth, profile abruptness and implant dose. For that purpose this paper presents a systematic study of the CI response to a wide variety of post anneal implant processes, varying parameters including implant species, dose and energy, annealing condition, and surface preparation.Samples containing B, BF2 and As-implants with and without Ge PAI layers, with junction depths between 10-120 nm, were measured. In addition near-ideal box-like profiles (as obtained with CVD-growth) were fabricated and measured. For the abrupt CVD profiles, CI measures the junction position with sub-nm resolution independent of the CI-analysis conditions. For more graded profiles resulting from annealed implants, the correlation to the SIMS junction depth becomes a function of generation laser current (which is proportional to the applied power). As the concentration level, at which the correlation is made, can be adjusted over a concentration range of approximately 2x1018 to 2x1019/cm3 by changing the laser current, a route towards correlating the CI measurement with profile abruptness becomes feasible.

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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.

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Quantitative parallel EELS spectrum imaging developed as a new tool in AEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013064x ◽

1992 ◽

Vol 50 (2) ◽

pp. 1202-1203

Author(s):

Gianluigi Botton ◽

Gilles L'espérance

Keyword(s):

Statistical Analysis ◽

Spatial Resolution ◽

Personal Computer ◽

Systematic Study ◽

Present Author ◽

Chemical Elements ◽

Detection Limits ◽

Research Groups ◽

Quantitative Performance ◽

Spectrum Imaging

As interest for parallel EELS spectrum imaging grows in laboratories equipped with commercial spectrometers, different approaches were used in recent years by a few research groups in the development of the technique of spectrum imaging as reported in the literature. Either by controlling, with a personal computer both the microsope and the spectrometer or using more powerful workstations interfaced to conventional multichannel analysers with commercially available programs to control the microscope and the spectrometer, spectrum images can now be obtained. Work on the limits of the technique, in terms of the quantitative performance was reported, however, by the present author where a systematic study of artifacts detection limits, statistical errors as a function of desired spatial resolution and range of chemical elements to be studied in a map was carried out The aim of the present paper is to show an application of quantitative parallel EELS spectrum imaging where statistical analysis is performed at each pixel and interpretation is carried out using criteria established from the statistical analysis and variations in composition are analyzed with the help of information retreived from t/γ maps so that artifacts are avoided.

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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.

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