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chemical degradation

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Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006921
EISBN: 978-1-62708-395-9
... four of the eight major aging mechanisms, namely environmental stress cracking, chemical degradation, creep, and fatigue, as well as the methods used in product service lifetime assessment for them. Later, several methods of service lifetime prediction that have gained industry-wide acceptance, namely...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006867
EISBN: 978-1-62708-395-9
... reagent. Finally, there are some chemicals that cause actual degradation of the polymer, breaking the macromolecular chains, reducing molecular weight, and diminishing polymer properties as a result. This article examines each of these effects. The discussion also covers the effects of surface...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006909
EISBN: 978-1-62708-395-9
... analytical (empirical, physical, or chemical) models. For the analytical model to be useful, the relationship between exposure and changes in material structure and properties should include degradation rates; dependence on environmental factors such as temperature, pressure, moisture content, or applied...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006866
EISBN: 978-1-62708-395-9
... Abstract Microbial degradation in the environment is initiated by abiotic (nonliving physical or chemical) processes. Mechanical weathering and other mechanical processes are the main drivers of the initial degradation. This article presents an overview of weathering and biodegradation...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003550
EISBN: 978-1-62708-180-1
... chemicals can induce environmental stress cracking (ESC), an effect in which brittle fracture of a polymer will occur at a level of stress well below that required to cause failure in the absence of the ESC reagent. Finally, there are some chemicals that cause actual degradation of the polymer, breaking...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c0090460
EISBN: 978-1-62708-234-1
... of molecular degradation caused by the service conditions. Specifically, the part material had undergone severe chemical attack, including oxidation and hydrolysis, through contact with silver chloride. The source of the silver chloride was not established, but one potential source was photographic silver...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001626
EISBN: 978-1-62708-235-8
... as adherent organic residue. Analysis by FTIR of the residue revealed detectable levels of two polymeric substances, which were later determined to be construction materials of the pickling tank. The latter conclusion suggests that the polymeric tank underwent chemical degradation from exposure...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.homegoods.c0090427
EISBN: 978-1-62708-222-8
... with glyceride derivatives of fats and oils. This supported the conclusion that the grips failed via brittle fracture associated with severe chemical attack of the ABS resin. A significant level of glyceride derivatives of fatty acids, known to degrade ABS resins, was found on the part surface. Chemical...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.auto.c9001901
EISBN: 978-1-62708-218-1
... to depolymerization if the backbones of the molecules are cleaved, thereby creating new unstable chain-ends. Backbones may be cleaved by chemical, mechanical, radiological, or thermal means. However, the only likely mechanisms for the sensor housing are chemical and/or thermal. In the worst case scenario...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.homegoods.c0090448
EISBN: 978-1-62708-222-8
... had been degraded, producing a reduction in the molecular weight and reducing both the mechanical integrity and chemical-resistance properties of the parts. Crystallization Electrical appliances Grease Housings Injection molding Molding resins Undercrystallization Polycarbonate...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001829
EISBN: 978-1-62708-241-9
..., and x-ray diffraction. It was shown that degradation is driven by chemical and mechanical differences, oxide growth, depletion, and recrystallization, the combined effect of which results in exfoliation, spallation, and mechanical thinning. turbine vanes thermal degradation high-temperature...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006920
EISBN: 978-1-62708-395-9
... properties such as tensile strength, color change, haze, or surface gloss. However, the degradation starts on the chemical level and often requires a long time until macroscopic degradation becomes detectable using these common evaluation methods. In recent years, progress has been made in understanding...
Series: ASM Failure Analysis Case Histories
Volume: 1
Publisher: ASM International
Published: 01 December 1992
DOI: 10.31399/asm.fach.v01.c9001109
EISBN: 978-1-62708-214-3
... accumulates with each cycle through the furnace. Metallographic and chemical analyses have clearly established that the grate bar degradation was primarily caused by hot corrosion by molten salts. The molten salt destroyed the ability of the material to maintain a protective oxide scale as a barrier...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001831
EISBN: 978-1-62708-241-9
... and contact surfaces. Chemical and thermal properties of the bearing grease were also examined. The investigation revealed that the failure was caused by wear due to dry friction and impact, both of which worsened as a result of high-temperature degradation of the bearing grease. Fatigue cracks initiated...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003525
EISBN: 978-1-62708-180-1
... of thermal oxidation, vinyl, vinylene functionality for photooxidation, and hydroxyl group formation indicating hydrolysis ( Ref 4 ). Case studies showing the effectiveness of FTIR in assessing molecular degradation are presented in examples 1 , 13 , and 15 in this article. Chemical Contact...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c9001628
EISBN: 978-1-62708-234-1
.... Comparative analysis of the fresh and used oil samples showed that the oil underwent some chemical degradation and moisture pickup while in use. Furthermore, some oxidation products from various system components were found in the used oil. Based on all these findings, the following scenario may have happened...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006926
EISBN: 978-1-62708-395-9
...) physical effects. Chemical attack occurs when chemical reactions result from the interaction between the environment and polymer molecules. This type of interaction may involve chain scission, the degradation of a polymer main chain, which is an irreversible effect. Crazing and microcracking, which...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006933
EISBN: 978-1-62708-395-9
... degradation; vinylene functionality for photooxidation; and hydroxyl group formation indicating hydrolysis ( Ref 5 ). Case studies showing the effectiveness of FTIR in assessing molecular degradation are presented in Examples 1, 13, and 15 in Ref 4 . Chemical Contact Similar to the application of FTIR...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c0046252
EISBN: 978-1-62708-229-7
... occurred in welded joints and in unwelded portions of the bellows. The bellows were made by forming the convolution halves from stainless steel sheet, then welding the convolutions together. Evidence from visual examination, liquid penetrant inspection chemical analysis, hardness tests, and metallographic...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006915
EISBN: 978-1-62708-395-9
... improve mechanical properties, their performance depends on orientation and fiber length, both of which can be affected by processing. Foams In foamed plastics a dispersed gaseous phase is incorporated into the plastic from the physical introduction of air or nitrogen, the degradation of chemical...