The Role of Chemical Bonding in the Adhesion of Elastomers

Abstract A review is given of several studies of the effect of interfacial bonding upon the mechanical strength of an adhesive joint. In the first, polybutadiene layers were crosslinked by a free radical process while in contact with silane-treated glass. A direct proportionality was found between the minimum peel strength of the joint, at high temperatures and low rates of peeling, and the vinyl content of the silane treatment liquid. Covalent bonding between the diene polymer and vinyl groups on the treated glass was inferred. When radioactively tagged silanes were employed, extensive combination with the glass substrates was demonstrated. Again, the greater the amount of vinyl silane found on the treated glass surface, the greater the mechanical strength of adhesion between the treated glass and a polybutadiene overlayer. In another series of experiments, two partially crosslinked sheets of polybutadiene were pressed together before the crosslinking was taken to completion. The additional crosslinking was determined from measurements of the elastic properties and of the degree of equilibrium swelling by a compatible liquid. Again, the mechanical strength of adhesion between the two sheets under threshold conditions was found to be directly proportional to the inferred degree of interfacial interlinking. Thus, at least at high temperatures and low rates of peel, there is substantial evidence for a direct correlation between the mechanical strength of a joint and the degree of interfacial chemical bonding. Moreover, the relationships established in these studies allow other bonding systems to be diagnosed as chemical or physical in nature. For example, a dramatic increase in the strength of adhesion between two crosslinked polybutadiene layers was observed if they were exposed to air or oxygen for periods of an hour or two before being pressed into contact. It is inferred that interfacial chemical bonds are formed as a consequence of rapid surface oxidation reactions.

Download Full-text

Tailoring Thermal Transport Properties by Inducing Surface Oxidation Reactions in Bulk Metal Composites

ACS Applied Materials & Interfaces ◽

10.1021/acsami.1c02792 ◽

2021 ◽

Author(s):

Islam Shancita ◽

Colton Cagle ◽

Irina Kalish ◽

Pascal Dubé ◽

Joseph Abraham ◽

...

Keyword(s):

Transport Properties ◽

Thermal Transport ◽

Surface Oxidation ◽

Oxidation Reactions ◽

Metal Composites ◽

Bulk Metal ◽

Thermal Transport Properties ◽

Inducing Surface

Download Full-text

Effect of interfacial chemical bonding on the strength of adhesion of glass–polybutadiene joints

Journal of Polymer Science Polymer Chemistry Edition ◽

10.1002/pol.1979.170170412 ◽

1979 ◽

Vol 17 (4) ◽

pp. 1067-1072 ◽

Cited By ~ 3

Author(s):

M. L. Runge ◽

P. Dreyfuss

Keyword(s):

Chemical Bonding ◽

Strength Of Adhesion

Download Full-text

Study of the Turning Nickel Base Alloy Pyromet® 31V (SAE HEV8)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.278.312 ◽

2011 ◽

Vol 278 ◽

pp. 312-320 ◽

Cited By ~ 2

Author(s):

Marcos Valério Ribeiro ◽

André Luís Habib Bahia

Keyword(s):

Thermal Conductivity ◽

Mechanical Strength ◽

High Temperatures ◽

Base Alloy ◽

Production Costs ◽

Machining Parameters ◽

Nickel Base Alloy ◽

Low Thermal Conductivity ◽

Nickel Base ◽

Coated Carbide

Considering the constant technological developments in the aeronautical, space, automotive, shipbuilding, nuclear and petrochemical fields, among others, the use of materials with high strength mechanical capabilities at high temperatures has been increasingly used. Among the materials that meet the mechanical strength and corrosion properties at temperatures around 815 °C one can find the nickel base alloy Pyromet® 31V (SAE HEV8). This alloy is commonly applied in the manufacturing of high power diesel engines exhaust valves where it is required high resistance to sulphide, corrosion and good resistance to creep. However, due to its high mechanical strength and low thermal conductivity its machinability is made difficult, creating major challenges in the analysis of the best combinations among machining parameters and cutting tools to be used. Its low thermal conductivity results in a concentration of heat at high temperatures in the interfaces of workpiece-tool and tool-chip, consequently accelerating the tools wearing and increasing production costs. This work aimed to study the machinability, using the carbide coated and uncoated tools, of the hot-rolled Pyromet® 31V alloy with hardness between 41.5 and 42.5 HRC. The nickel base alloy used consists essentially of the following components: 56.5% Ni, 22.5% Cr, 2,2% Ti, 0,04% C, 1,2% Al, 0.85% Nb and the rest of iron. Through the turning of this alloy we able to analyze the working mechanisms of wear on tools and evaluate the roughness provided on the cutting parameters used. The tests were performed on a CNC lathe machine using the coated carbide tool TNMG 160408-23 Class 1005 (ISO S15) and uncoated tools TNMG 160408-23 Class H13A (ISO S15). Cutting fluid was used so abundantly and cutting speeds were fixed in 75 and 90 m/min. to feed rates that ranged from 0.12, 0.15, 0.18 and 0.21 mm/rev. and cutting depth of 0.8mm. The results of the comparison between uncoated tools and coated ones presented a machined length of just 30% to the first in relation to the performance of the second. The coated tools has obtained its best result for both 75 and 90 m/min. with feed rate of 0.15 mm/rev. unlike the uncoated tool which obtained its better results to 0.12 mm/rev.

Download Full-text

Surface Oxidation Behaviour of Cubic BN Powders

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.544 ◽

2014 ◽

Vol 602-603 ◽

pp. 544-547

Author(s):

Xin Yan Yue ◽

Yue Zhang ◽

Jian Jun Wang ◽

Wei Wang ◽

Hong Qiang Ru

Keyword(s):

Heat Treatment ◽

Surface Oxidation ◽

Mass Gain ◽

Oxidation Behaviour ◽

Experimental Results ◽

Oxidation Temperature ◽

Oxidation Reactions ◽

Oxidation Treatment ◽

Treatment Processes

In order to improve the sinterability of the cBN, surface oxidation treatment was conducted to form a B2O3 film on the surface of the cBN powders. The cBN powders (d50 = 7.5 μm) were used as original powders. The heat treatment processes were 500, 800, 900, 950, 980 and 1000 °C holding for 30 minutes, respectively. The oxidation reactions which probably happened were calculated based on the thermodynamics. The experimental results showed that the oxidation starting temperature of cBN powders was higher than 800 °C. The higher the oxidation temperature, the greater the mass gain of the cBN powders.

Download Full-text

Sliding Wear Performance of AlCrN Coating on TiB2/Ti Composites at High Temperatures

Materials ◽

10.3390/ma14226771 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6771

Author(s):

Remigiusz Michalczewski ◽

Marek Kalbarczyk ◽

Zbigniew Słomka ◽

Edyta Osuch-Słomka ◽

Maciej Łuszcz ◽

...

Keyword(s):

Wear Resistance ◽

High Temperatures ◽

Surface Oxidation ◽

Manufacturing Technology ◽

Tribological Behaviour ◽

Composite Surface ◽

Group Iii ◽

High Adhesion ◽

Group I ◽

Coating Composite

The aim of the study was to investigate effect of Ti/TiB2 composite composition and manufacturing technology parameters on the tribological behaviour of AlCrN coating-composite system. The AlCrN coating was deposited by PVD (Physical Vapour Deposition) method. The composites were manufactured by spark plasma sintering (SPS) from three variants of powders mixtures: Ti with TiB2, Ti6Al4V with TiB2 as well as Ti with B, using (five) different sintering temperatures. For each of the developed coating-composite systems, the wear resistance was evaluated using ball-on-disc SRV tester, at six temperatures (from room temperature up to 900 °C). The results confirmed that high-temperature wear resistance of the coating–substrate combination depends on Ti/TiB2 composite composition and manufacturing technology parameters. In the case of uncoated composite, two processes manage the wear at high temperatures: cracking propagation and surface oxidation. The presence of AlCrN coating on the composite surface protects the surface against deep cracking and surface oxidation. The composites of Group I, sintered at 1250 °C from a mixture of pure Ti and TiB2 (50/50 wt.% ratio) as well as Group III, sintered at 1350 °C from a mixture of pure Ti and B allow the achievement of a satisfactory surface quality, a high adhesion of the PVD coating and moderate wear at high temperatures. However, the composite made of pure Ti and B seems to be a better solution for temperatures exceeding 600 °C.

Download Full-text

Adhesion Improvement and Characterization of Magnetron Sputter Deposited Bilayer Molybdenum Thin Films for Rear Contact Application in CIGS Solar Cells

International Journal of Photoenergy ◽

10.1155/2016/2124087 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 8

Author(s):

Weimin Li ◽

Xia Yan ◽

Armin G. Aberle ◽

Selvaraj Venkataraj

Keyword(s):

Thin Films ◽

Solar Cells ◽

Magnetron Sputtering ◽

Surface Oxidation ◽

Bottom Layer ◽

Soda Lime ◽

Soda Lime Glass ◽

Individual Layer ◽

Glass Substrates ◽

Cigs Solar Cells

Molybdenum (Mo) thin films are widely used as rear electrodes in copper indium gallium diselenide (CIGS) solar cells. The challenge in Mo deposition by magnetron sputtering lies in simultaneously achieving good adhesion to the substrates while retaining the electrical and optical properties. Bilayer Mo films, comprising five different thickness ratios of a high pressure (HP) deposited bottom layer and a low pressure (LP) deposited top layer, were deposited on 40 cm × 30 cm soda-lime glass substrates by DC magnetron sputtering. We focus on understanding the effects of the individual layer properties on the resulting bilayer Mo films, such as microstructure, surface morphology, and surface oxidation. We show that the thickness of the bottom HP Mo layer plays a major role in determining the micromechanical and physical properties of the bilayer Mo stack. Our studies reveal that a thicker HP Mo bottom layer not only improves the adhesion of the bilayer Mo, but also helps to improve the film crystallinity along the preferred [110] direction. However, the surface roughness and the porosity of the bilayer Mo films are found to increase with increasing bottom layer thickness, which leads to lower optical reflectance and a higher probability for oxidation at the Mo surface.

Download Full-text

Enhanced Adhesion Strength of Pt/γ-Al2O3 Catalysts on STS-444 Substrate via γ-Al2O3 Intermediate Layer Formation: Application for CO and C3H6 Oxidation

Catalysts ◽

10.3390/catal12010038 ◽

2021 ◽

Vol 12 (1) ◽

pp. 38

Author(s):

Seung-Hee Ryu ◽

Cheol Hong Hwang ◽

Hojin Jeong ◽

Giyeong Kim ◽

Sung Il Ahn ◽

...

Keyword(s):

Adhesion Strength ◽

Intermediate Layer ◽

Substrate Surface ◽

Surface Oxidation ◽

Catalytic Performance ◽

Pack Cementation ◽

Oxidation Reactions ◽

Monolithic Catalysts ◽

Simultaneous Oxidation ◽

Potential Applications

Pt/γ-Al2O3 catalysts coated on honeycomb-shaped stainless STS-444 steel substrates with a γ-Al2O3 intermediate layer were prepared using a conventional washcoating method. The intermediate layer was formed on the substrate surface through oxidation using pack cementation. The monolithic catalysts with the intermediate layer were fabricated for potential applications to pre-turbocharger catalysts, which suffer from severe conditions such as vibrations of the engine and high flow rates of exhaust gas. Adhesive strength tests and simultaneous oxidation reactions of CO and C3H6 were carried out for the Pt/γ-Al2O3 monolithic catalysts with and without the intermediate layer. The catalysts with an intermediate layer showed much stronger adhesion than the catalysts without an intermediate layer. Thus, the formation of a γ-Al2O3 intermediate layer by surface oxidation through pack cementation facilitated a significant enhancement of the catalyst adhesion strength without catalytic performance degradation.

Download Full-text

Energy Coupling of Laser Radiation on AISI 304 Stainless Steel: Effect of High Temperatures and Surface Oxidation

Materials ◽

10.3390/ma12172802 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2802 ◽

Cited By ~ 1

Author(s):

Hipp ◽

Mahrle ◽

Beyer

Keyword(s):

Stainless Steel ◽

Melting Point ◽

High Temperatures ◽

Coupling Efficiency ◽

Surface Oxidation ◽

Energy Coupling ◽

304 Stainless Steel ◽

Effect Of Temperature ◽

Laser Material Processing ◽

Laser Materials

The industrial application of laser materials processing methods is still far ahead of research into the physical phenomena occurring during these processes. In particular, the effect of high temperatures on the energy coupling of laser irradiation of metals is poorly understood. However, most processes in laser materials treatment involve temperatures above the melting point or even cause evaporation. This study therefore evaluates the effect of high temperatures on the energy coupling efficiency of stainless steel experimentally for three typical laser wavelengths (515 nm, 1.07 µm, 10.6 µm). As a result, it is shown that the effect of temperature on the energy coupling efficiency depends on the wavelength. In this context the relevance of the X-point phenomenon known from the emissivity theory could be demonstrated for laser material processing. Further, the effect of a process-induced surface oxidation is analyzed. At temperatures above 650 °C the energy coupling efficiency dramatically increases to around 65% at melting point and stays at this high level even in the liquid phase.

Download Full-text

Adhesive Enabling Technology for Directly Plating Copper onto Glass

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/2014dpc-tha12 ◽

2014 ◽

Vol 2014 (DPC) ◽

pp. 001913-001936

Author(s):

Lutz Brandt ◽

Zhiming Liu ◽

Hailuo Fu ◽

Sara Hunegnaw ◽

Tafadzwa Magaya

Keyword(s):

Metal Oxide ◽

Oxide Layer ◽

High Speed ◽

Sol Gel ◽

Peel Strength ◽

Significant Loss ◽

Organic Substrates ◽

New Approach ◽

Glass Substrates ◽

Metal Oxide Layer

Reliable adhesion of copper to glass is a major hurdle for the entry of glass substrates into the electronic packaging market. Otherwise, glass is a strong competitor to organic substrates due to its superior flatness, thermal and dielectric properties. These are essential requirements for high density interconnects, high speed signal transfer and IC substrate packaging. Typically, adhesion on glass is achieved by sputtering a thin metallic adhesive (Ti) and copper seed layer followed by galvanic plating. This paper presents a promising wet-chemical alternative to sputtering. In this new approach a 50-200 nm thick adhesive metal oxide layer is deposited by a modified sol gel process followed by sintering, thus enabling electroless, and galvanic metal plating directly on glass. Formerly the thickness of the galvanic copper layer constituted a major challenge leading to its facile delamination from the glass. With the new approach, Cu film thickness of over 50 μm can be applied without delamination. Adhesion at 15 μm Cu thickness as measured by 90o peel strength tests can achieve 5 N/cm or even higher values, while 2 N/cm appear to be sufficient to prevent delamination. In comparison, Ti/Cu sputtered glass substrates achieve at best 1.5 N/cm at the same copper thickness, while electroless Cu seeded glass substrates without the adhesive metal oxide layer show no adhesion. The effect of glass roughness on adhesion was also studied. It does appear to have only a marginal impact on adhesion. On the other hand, the glass type has bearing on the achievable adhesion values. The plated layer stands up well to reflow shock (260C) and HAST without significant loss of adhesion. Good adhesion has been also demonstrated inside the via holes of patterned substrates without indication of blockages by the process. The process is versatile in that it is also applicable to ceramic substrates such as aluminum oxide.

Download Full-text