Effects of Inhibited Acid Cleaning of Steel Fracture Surfaces for Failure Analyses

2007 ◽  
Vol 8 (1) ◽  
pp. 12-19
Author(s):  
Michael J. Mullen ◽  
Arthur H. Griebel ◽  
John M. Tartaglia
CORROSION ◽  
1960 ◽  
Vol 16 (10) ◽  
pp. 18-26
Author(s):  
Charles M. Loucks

Abstract Author believes little more attention is being paid to corrosion control in chemical cleaning operations than was common in 1957 when the first NACE committee on the subject was organized. History of chemical cleaning is reviewed, with references to the literature dealing with the use of petroleum products, potatoes and other materials. First use of acids is described and some engineers’ comments on use of acids are reported. Following the introduction of inhibited acids for cleaning, the growth of contract cleaning is described. Some laboratory and field experience with cleaning by inhibited acid is described, and some of the corrosion and safety hazards examined. In considering the contract cleaning of plants with acids, the author cites the difficulties faced in attempting to establish specifications for the work in advance of contract letting. He deplores the practice of letting acid cleaning on the lowest bid without a full understanding between the parties of what is to be done. Writer suggests that the nature of the acid cleaning process is such, the potential hazards to persons and equipment so serious that industry would be advised to seek professional type services rather than let work on low bids. Some mention is made of cleaning agents other than hydrochloric acids and why contractors so far have shown little interest in them. 49 references. 5.9.2


Author(s):  
Russell L. Steere ◽  
Eric F. Erbe

Thin sheets of acrylamide and agar gels of different concentrations were prepared and washed in distilled water, cut into pieces of appropriate size to fit into complementary freeze-etch specimen holders (1) and rapidly frozen. Freeze-etching was accomplished in a modified Denton DFE-2 freeze-etch unit on a DV-503 vacuum evaporator.* All samples were etched for 10 min. at -98°C then re-cooled to -150°C for deposition of Pt-C shadow- and C replica-films. Acrylamide gels were dissolved in Chlorox (5.251 sodium hypochlorite) containing 101 sodium hydroxide, whereas agar gels dissolved rapidly in the commonly used chromic acid cleaning solutions. Replicas were picked up on grids with thin Foimvar support films and stereo electron micrographs were obtained with a JEM-100 B electron microscope equipped with a 60° goniometer stage.Characteristic differences between gels of different concentrations (Figs. 1 and 2) were sufficiently pronounced to convince us that the structures observed are real and not the result of freezing artifacts.


Author(s):  
Russell L. Steere ◽  
Michael Moseley

A redesigned specimen holder and cap have made possible the freeze-etching of both fracture surfaces of a frozen fractured specimen. In principal, the procedure involves freezing a specimen between two specimen holders (as shown in A, Fig. 1, and the left side of Fig. 2). The aluminum specimen holders and brass cap are constructed so that the upper specimen holder can be forced loose, turned over, and pressed down firmly against the specimen stage to a position represented by B, Fig. 1, and the right side of Fig. 2.


Author(s):  
Russell L. Steere

Complementary replicas have revealed the fact that the two common faces observed in electron micrographs of freeze-fracture and freeze-etch specimens are complementary to each other and are thus the new faces of a split membrane rather than the original inner and outer surfaces (1, 2 and personal observations). The big question raised by published electron micrographs is why do we not see depressions in the complementary face opposite membrane-associated particles? Reports have appeared indicating that some depressions do appear but complementarity on such a fine scale has yet to be shown.Dog cardiac muscle was perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (material furnished by Dr. Joaquim Sommer, Duke Univ., and VA Hospital, Durham, N.C.). Small strips were freeze-fractured in a Denton Vacuum DFE-2 Freeze-Etch Unit with complementary replica tooling. Replicas were cleaned in chromic acid cleaning solution, then washed in 4 changes of distilled water and mounted on opposite sides of the center wire of a Formvar-coated grid.


Author(s):  
Kathleen B. Reuter

The reaction rate and efficiency of piperazine to 1,4-diazabicyclo-octane (DABCO) depends on the Si/Al ratio of the MFI topology catalysts. The Al was shown to be the active site, however, in the Si/Al range of 30-200 the reaction rate increases as the Si/Al ratio increases. The objective of this work was to determine the location and concentration of Al to explain this inverse relationship of Al content with reaction rate.Two silicalite catalysts in the form of 1/16 inch SiO2/Al2O3 bonded extrudates were examined: catalyst A with a Si/Al of 83; and catalyst B, the acid/phosphate Al extracted form of catalyst A, with a Si/Al of 175. Five extrudates from each catalyst were fractured in the transverse direction and particles were obtained from the fracture surfaces near the center of the extrudate diameter. Particles were also obtained from the outside surfaces of five extrudates.


2019 ◽  
Vol 20 (3) ◽  
pp. 147-152
Author(s):  
Ha Na Seo ◽  
Yu Gyung Kim ◽  
Yeong Seon Park ◽  
Byeong Wook Kong ◽  
Deog Gwan Ra ◽  
...  
Keyword(s):  

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1048
Author(s):  
Belén Díaz ◽  
X. Ramón Nóvoa ◽  
Carmen Pérez ◽  
Sheila Silva-Fernández

This research emphasizes the importance of the acid cleaning prior to the phosphate development on high-strength steel rods. It compares the phosphate properties achieved after different acid-pickling conditions. The most common inorganic acids were considered in this study. Additionally, taking into account the environmental and safety concerns of these acids, the assessment of a less harmful organic acid is presented. This study revealed significant differences in the coating morphology and chemical composition whereas no great changes were found in terms of the coating weight or porosity. Thus, hydrochloric and sulfuric acid promote the growth of a Fe-enriched phosphate layer with a less conductive character that is not developed after the pickling with phosphoric acid. The phosphate developed after the citric acid pickling is comparable to that developed after the inorganic acids although with a porosity slightly higher. The temperature of the citric acid bath is an important parameter that affects to the phosphate appearance, composition, and porosity.


2015 ◽  
Vol 13 (0) ◽  
pp. 159-163
Author(s):  
Hiroki Kanehira ◽  
Muhammad Zainurin ◽  
Shuji Shimamura

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