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Article
Publication date: 1 June 1998

Michael Frederickson

Organic and immersion metallic coatings are being used as a replacement for the hot air solder level (HASL) process. Use of these coatings provides advantages for both the…

Abstract

Organic and immersion metallic coatings are being used as a replacement for the hot air solder level (HASL) process. Use of these coatings provides advantages for both the fabricator and assembler. Advantages to assemblers include flatter pads (0.25‐0.5 micron thickness), no limitations on fine pitch or small hole cleaning, and greater solder joint strength. Advantages to the fabricator include lower operating costs, little or no rejects/rework, reduced safety hazard and a more environmentally friendly process. Current problems associated with the organic and immersion coatings include the inability to assess the solderability of the bare copper or the integrity of the coating (organic). These coatings also present a critical concern due to their reduced shelf life and potential inability to survive mishandling in manufacturing. Real time, non‐destructive methods of rapidly assessing the integrity these coatings are currently not available to the electronics industry. Surface Spectroscopy measurement techniques have the potential to measure the structure and characteristics of the organic and metallic coatings, and surface oxides that develop with time and temperature. The measurement techniques are rapid, non‐contact, and relatively inexpensive to make when compared to existing methods. Surface Spectroscopy can also provide critical surface information that is needed to troubleshoot solderability problems. The American Competitiveness Institute in association with the Navy EMPF program is working with several industry partners to develop a usable surface spectroscopy tool that will assess the quality and integrity of the coatings and correlate that reading with a solderability evaluation.

Details

Circuit World, vol. 24 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 September 1979

M.A. Adams

Background In the language of the steel industry, the term coated steel means, for all practical purposes, mild steel sheet or strip which is coated before it leaves the…

Abstract

Background In the language of the steel industry, the term coated steel means, for all practical purposes, mild steel sheet or strip which is coated before it leaves the steel mill. Various coatings are employed depending upon product end use but basically they divide up into metallic coatings such as tin, zinc or aluminium; and organic coatings which are essentially paints or plastic films. Organic coatings are very often applied on top of metallic coatings, so that in the most advanced coated products there may be as many as five separate layers of material between the underlying steel and the exposed outer surface.

Details

Anti-Corrosion Methods and Materials, vol. 26 no. 9
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 24 January 2020

Guiyang Wu, Qiang Zhang and Nange Zhang

Organic coatings are one of the most widely applied methods for corrosion protection of metallic materials such as the tubing used in sour gas field. However, such coatings

Abstract

Purpose

Organic coatings are one of the most widely applied methods for corrosion protection of metallic materials such as the tubing used in sour gas field. However, such coatings usually encounter the risk of failure due to the harsh and complex environment. Therefore, the study of failure of the organic coating is highly significant.

Design/methodology/approach

In this paper, the effects of Cl-concentration, HCl content, hydrogen sulfide/carbon dioxide (H2S/CO2), temperature and flow rate on the failure of epoxy-phenolic coating on the internal surface of BG90S steel tubing were investigated using adhesion force measurement, metallographic microscope, electrochemistry impedance spectroscopy and Fourier transform infrared spectroscopy.

Findings

The results show that the Cl-concentration, HCl content and H2S/CO2 do not affect the failure process too much as the ion concentration increased. However, the flow rate at the high temperature is the most important factor affecting the corrosion resistance of the inner coating tubing. With the increase of the flow rate, the pore resistance of the coating shows a decreasing trend, and the rate of decrease in pore resistance is first rapid and then slow. It demonstrates that the penetration speed of the electrolyte solution into the coating varied from fast to slowly. A weakening influence of the flow rate on the penetration failure of the inner coating can be found as the increase of the flow rate. Once the HS-ions penetrate through the coating and reach at the coating/steel interface where H2 could be formed through the adsorption reaction, the coating failure occurs.

Originality/value

The failure of the coating depends on the penetration rate of water and ions, with the presence of exposed or punctured holes is accelerated and HS- was adsorpted by substrate Fe, and form H2 molecules between the coatings and substrate, that results failure of coatings.

Details

Pigment & Resin Technology, vol. 49 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 February 1994

I. Artaki, U. Ray, A.M. Jackson, H.M. Gordon and P.T. Vianco

Substitution of lead‐free solders in electronic assemblies requires changes in the conventional Sn:Pb finishes on substrates and component leads to prevent contamination…

Abstract

Substitution of lead‐free solders in electronic assemblies requires changes in the conventional Sn:Pb finishes on substrates and component leads to prevent contamination of the candidate solder. Options for solderability preservative coatings on the printed wiring board include organic (azole or rosin/resin based) films and tin‐based plated metallic coatings. This paper compares the solderability performance of electroless tin coatings versus organic azole films after exposure to a series of humidity and thermal cycling conditions. It is shown that the solderability of immersion tin is directly related to the tin oxide growth on the surface and is not affected by the formation of Sn‐Cu intermetallic phases as long as the intermetallic phase is protected by a surface Sn layer. For a nominal tin thickness of 60 ?inches, the typical thermal excursions associated with assembly were not sufficient to cause the intermetallic phase to consume the entire tin layer. Exposure to elevated temperatures, in the presence of humidity, promoted heavy tin oxide formation which led to solderability loss. In contrast, thin azole films were shown to be more robust to humidity exposure; however, upon heating in the presence of oxygen, they decomposed and led to severe solderability degradation. Evaluations of lead‐free solder pastes for surface mount assembly applications indicated that immersion tin significantly improved the spreading of Sn:Ag and Sn:Bi alloys compared with azole surface finishes.

Details

Circuit World, vol. 20 no. 3
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 17 February 2021

Botros Meglaa, Magda Tawfik, Fatma Morsy, Samya Elsherbiny and Hisham Essawy

Automotive coating materials are very important items for this industry. However, their performance is limited by the use of excessive amounts of solvents in their…

Abstract

Purpose

Automotive coating materials are very important items for this industry. However, their performance is limited by the use of excessive amounts of solvents in their formulations, whereas the emission of volatile organic solvents is against the widely ascending principle of green chemistry. Thus, this study aims to overcome this global problem to save the environment without affecting the properties and performance of the coating.

Design/methodology/approach

High solid content paint formulation for automotive applications has been designed with low amount of volatile organic solvents with the aid of a functionalized hyperbranched modifier.

Findings

It was found that the presence of a hyperbranched additive allows a high solid content to be designed and facilitate the processing, which indicates its liability to compensate the role played by excessive solvents amounts. In addition, the mechanical properties and physical characteristics of the modified coatings showed outstanding performance and preservation of clarity in comparison with the commercial counterparts.

Practical implications

A high solid content coating with facile processing and improved performance leads to cheaper price beside the positive impact on the environment considering the limited emission of volatile organic contents.

Social implications

Limitation of the used volatile organic compounds in any industry helps to save the health of humans and keep the environment unaffected.

Originality/value

The use of functionalized hyperbranched additive to automotive coatings is a very promising additive for automotive coatings with optimized characteristics.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 September 2015

Rami Mohammad Suleiman

The purpose of this paper was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5…

Abstract

Purpose

The purpose of this paper was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5 per cent NaCl solution. The search for replacing chromates in protective coatings has led to the development of hybrid sol-gel anticorrosive coatings. Appropriate functionalization can dramatically enhance the chemical durability and mechanical strength of these coatings.

Design/methodology/approach

To prepare the targeted coating, 1,2-epoxybutane (EB) was mixed with 2 to 4 per cent aminoethylaminopropyl-methylsiloxane dimethylsiloxane (APDMS) copolymer and 1,6-diaminohexane. The above coating (EBAC) has been further mixed with three different corrosion inhibitors “Moly-white® 101-ED, Heucophos Zapp® and cerium ammonium nitrate”, yielding the coatings EBAC-M, EBAC-Z and EBAC-Ce, respectively. The corrosion characteristics of all coatings on the steel panels immersed in 3.5 per cent NaCl solution were obtained using different electrochemical methods such as electrochemical impedance spectroscopic and Tafel polarization measurements.

Findings

The newly prepared coatings showed interesting protection properties for protecting the steel substrate against corrosion in chloride-containing media.

Originality/value

The results provide a good approach for the modification of polydimethylsiloxane coatings using a simple organic modifier.

Details

Anti-Corrosion Methods and Materials, vol. 62 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 October 2014

Rami Mohammad Suleiman

The purpose of this work was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5…

Abstract

Purpose

The purpose of this work was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5 per cent NaCl solution. The search for replacing chromates in protective coatings has led to the development of hybrid sol-gel anticorrosive coatings. Appropriate functionalization can dramatically enhance the chemical durability and mechanical strength of these coatings.

Design/methodology/approach

To prepare the targeted coating, 1,2-epoxybutane (EB) was mixed with 2-4 per cent aminoethylaminopropyl-methylsiloxane dimethylsiloxane copolymer and 1,6-diaminohexane. The above coating (EBAC) was further mixed with three different corrosion inhibitors “Moly-white® 101-ED, Hfucophos Zapp®” and Cerium Ammonium Nitrate, yielding the coatings (EBAC-M), (EBAC-Z) and (EABC-Ce), respectively. The corrosion characteristics of all coatings on carbon steel panels immersed in 3.5 per cent NaCl solution were obtained using different electrochemical methods such as electrochemical impedance spectroscopic and Tafel polarization measurements.

Findings

The newly prepared coatings showed interesting properties for protecting the steel substrate against corrosion in chloride containing media.

Originality/value

The results provide a good approach for the modification of polydimethylsiloxane coatings using a simple organic modifier.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 5 July 2011

R. Otáhal, D. Veselý, J. Násadová, V. Zíma, P. Němec and P. Kalenda

The purpose of this paper is to study properties of intumescent coatings based on a silicone‐epoxy hybrid resin (with an aminosilane as hardener). In the first part of…

Abstract

Purpose

The purpose of this paper is to study properties of intumescent coatings based on a silicone‐epoxy hybrid resin (with an aminosilane as hardener). In the first part of this study, fire‐resistance behaviour of the intumescent coating based on silicone‐epoxy resin containing intumescent additives is evaluated. The second part assesses the effect of mineral fibres on fire‐resistant properties of intumescent coatings based on the silicone‐epoxy resin.

Design/methodology/approach

Thermal degradation and char formation of coatings were investigated by Thermogravimetric analyses, X‐ray diffraction and X‐ray fluorescence and infrared spectroscopy (FTIR). The salt spray corrosion test was applied to study the resistance of intumescent coatings. Anticorrosion and fire‐resistant properties after one, three and seven days of exposure were evaluated.

Findings

It was shown that a silicone‐epoxy hybrid resin is suitable for applications in the field of intumescent coatings. Intumescent coatings based on this resin form a thermally stable thin ceramic‐like layer, which improves the thermal insulation properties of the char. Mineral fibres reinforced the char structure and thus improved fire‐resistant properties of intumescent coating before as well as after the salt spray test. Mineral fibres also improved anticorrosion properties.

Research limitations/implications

This paper discusses only the effect of mineral fibres on properties of intumescent coatings.

Originality/value

A silicone‐epoxy hybrid resin has not previously been used in intumescent coatings. This type of intumescent coating can be used as an effective passive fire protection system for steel constructions.

Details

Pigment & Resin Technology, vol. 40 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 3 November 2014

N.A. Mat Nor, L. Ismail, S.K.M. Jamari, K. Ramesh, B. Vengadaesvaran and A.K. Arof

This paper aims to analyse the coating behaviour in corrosion environment as well as to evaluate the best percentage amount of copper oxide and copper needed for organic

Abstract

Purpose

This paper aims to analyse the coating behaviour in corrosion environment as well as to evaluate the best percentage amount of copper oxide and copper needed for organic coating in order to prevent the corrosion degradation. Electrochemical impedance spectroscopy (EIS) studies have been conducted in order to evaluate the corrosion performance of polyester-epoxy-copper oxide and polyester-epoxy-copper coating systems.

Design/methodology/approach

The availability of this modem instruments is used to obtain impedance data as well as computer programs to interpret the results that made the technique popular. In addition, EIS is well suited to the study of polymer-coated metals.

Findings

The results showed that samples containing 25 weight per cent of copper oxide and copper (90P25CuO and 90P25Cu) obtained the excellent corrosion properties from the first day up to 30 days of NaCl immersion. The highest corrosion resistance values obtained by 90P25CuO and 90P25Cu on the 30th day were 7.107 × 108 O and 5.701 × 108 O, respectively, with lower double layer capacitance of 1.407 × 10−9 Farad and 3.935 × 10−9 Farad, respectively. Moreover, the water uptake gained by these two coating samples was the lowest at the end of immersion, which was 0.0084 for 90P25CuO and 0.1592 for 90P25Cu, showing that the sample has good corrosion performance.

Originality/value

This paper discussed on the highest corrosion resistance, double layer capacitance and the water uptake of the copper (Cu) and copper oxide (CuO) coating system obtained from the EIS measurements.

Details

Pigment & Resin Technology, vol. 43 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 23 May 2008

D. Veselý and A. Kalendová

The purpose of this paper is to describe the process of synthesizing lamellarly‐shaped anticorrosion pigments having a chemically active layer whose core consists of metal…

Abstract

Purpose

The purpose of this paper is to describe the process of synthesizing lamellarly‐shaped anticorrosion pigments having a chemically active layer whose core consists of metal aluminium on which a thin spinel film is synthesised.

Design/methodology/approach

Anticorrosion pigments were synthesised by reaction of metal aluminium lamellar particles whose surface was oxidised to Al2O3 during the first stage and by subsequent reaction with ZnO and/or MgO at 800‐1,150°C producing a thin spinel layer that is chemically bonded to the metal core of the pigment particles. Core‐shell pigments including MgAl2O4/Al, Mg0.8Zn0.2Al2O4/Al, Mg0.6Zn0.4Al2O4/Al, Mg0.4Zn0.6Al2O4/Al, Mg0.2Zn0.8Al2O4/Al and ZnAl2O4/Al were synthesised. The prepared pigments were characterised by means of X‐ray diffraction analysis and scanning electron microscopy. The synthesised anticorrosion pigments were used to prepare epoxy coatings that were tested upon application for their anticorrosion properties and resistance against a chemical environment.

Findings

The lamellar shape of the particles, as well as good‐quality coverage with a thin spinel layer, was identified in the prepared pigments. All of the synthesised pigments exhibit good anticorrosion efficiency in epoxy coatings. Compared to lamellar kaolin and metal core of aluminium without coverage, the protective function of the synthesised pigments in coatings is demonstrably better.

Practical implications

The synthesised pigments find convenient applications in coatings protecting metal bases from corrosion.

Originality/value

Synthesis of a spinel layer on the metal core of aluminium is a novel method; so is the application of these substances in coatings designed for the protection of metals from corrosion. Of great benefit is the fact that the synthesised pigments are free of any substances harmful to the environment.

Details

Pigment & Resin Technology, vol. 37 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

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