Increased Filiform Corrosion Resistance Utilizing a Zirconium-Based Conversion Coating on an Al-Zn-Mg-Cu (AA7075-T6) Alloy as well as Selected Surface Treatments

CORROSION ◽  
10.5006/3510 ◽  
2020 ◽  
Author(s):  
Carol Glover ◽  
Mary Lyn Lim ◽  
John Scully
Keyword(s):  
Surface Treatment ◽  
Photoelectron Spectroscopy ◽  
Conversion Coating ◽  
Surface Treatments ◽  
Treatment Processes ◽  
Filiform Corrosion ◽  
Alkaline Cleaning ◽  
Vinyl Butyral ◽  
Subsequent Acid ◽  
Effect Of Surface

This study investigates the effect of surface treatment on the formation of Zr-based conversion coatings on AA7075-T6 automotive aluminum alloys and their resistance to filiform corrosion (FFC). Two different surface treatments were studied (A) alkaline-cleaning and (B) alkaline-cleaning with a subsequent acid deoxidation step. A model poly-vinyl butyral (PVB) primer coating was used as the topcoat and specimens were studied with and without the application of a Zr-based conversion coating. Comparisons were made against a control that had no surface treatment. The FFC filament initiation time and propagation kinetics were of particular interest. Scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS) were used to examine the conversion coating thickness and composition. A bi-layer conversion coating structure is demonstrated and both surface treatments are shown to produce copper enrichment that promotes the formation of the Zr-rich coating. Specimens prepared by alkaline cleaning-only resulted in a substantially thicker oxide layer of which 97% was ZrO2. These specimens provide superior resistance to FFC where the thick Zr-rich oxide is thought to provide a dense blocking layer that prevents electron transfer at the interface. In contrast, the control specimen, exposed only to the copper additions present in the conversion bath is shown to produce an Al oxide-rich layer with only a 33% ZrO2 contribution in the outer layer. The findings demonstrate that the redistribution of functional copper species, that is shown to occur during surface treatment processes, is crucial for the formation of a robust Zr film.

The Effect of Surface Treatment on the Performance of a Trivalent Chromium Process (TCP) Pretreatment on AA7075 Aerospace Alloys for the Protection Against Filiform Corrosion

CORROSION ◽  
10.5006/3380 ◽  
2019 ◽  
Vol 75 (12) ◽  
pp. 1513-1526 ◽  
Author(s):  
C.F. Glover ◽  
M.L.C. Lim ◽  
G. Post ◽  
M. Mayo ◽  
J.R. Scully
Keyword(s):  
Surface Treatment ◽  
Oxide Layer ◽  
Surface Characterization ◽  
Polyvinyl Butyral ◽  
Trivalent Chromium ◽  
Conversion Coating ◽  
Surface Treatments ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Filiform Corrosion

The performance of a trivalent chromium process (TCP) pretreatment conversion coating, applied to AA7075 aerospace aluminum alloys, for its ability to improve the filiform corrosion (FFC) of a polyvinyl-butyral coating, was studied as a function of surface treatment. Data from atmospheric FFC and full-immersion corrosion experiments are compared with surface characterization data to gain an understanding of the FFC kinetics on this alloy and mechanism by which the TCP coating provides inhibition. Specimens were prepared with three different surface treatments and studied with and without a TCP pretreatment conversion coating. A biphasic layer incorporating a zirconium-chromium mixed oxide outer layer and a fluoroaluminate interfacial layer was observed on all pretreated specimens. Enhanced corrosion protection by the TCP coating was observed when an acid pickle surface treatment was applied and the FFC filament propagation was stifled with an efficiency of 86%. A zirconium-rich outer oxide layer of approximately 22 nm, more than double the thickness of that measured for the other surface-treatments, is reported. Such layers are reported to be sufficiently dense so as to block ion transport from solution to the alloy surface. This acid pickle surface treatment is shown to effectively reduce the thickness of the native oxide layer and remove intermetallic particles from the surface enabling the formation of a more homogeneous TCP layer. Furthermore, Cu replating resulting from an acidic deoxidation step is shown to have no discernable effect on FFC.

scholarly journals Effect of surface treatments on push-out bond strength of calcium silicate-based cements to fiber posts

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Amr M. Elnaghy ◽  
Ayman Mandorah ◽  
Ali H. Hassan ◽  
Alaa Elshazli ◽  
Shaymaa Elsaka
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Glass Fiber ◽  
Calcium Silicate ◽  
Surface Treatments ◽  
The Other ◽  
Fiber Posts ◽  
Glass Fiber Posts ◽  
Push Out ◽  
Effect Of Surface

Abstract Background To evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts. Methods Two brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post (n = 80/group) was divided into four groups (n = 20/group) and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF4 4 wt/v%. Each group was further subdivided into two subgroups (n = 10/subgroup) based on the type of CSCs used as follows: Subgroup A: BD and Subgroup B: WMTA. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed using three-way ANOVA and Tukey’s test. A Weibull analysis was performed on the push-out bond strength data. Results BD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF4 4 wt/v% showed the greater characteristic bond strength (σ0) (15.93) compared with the other groups. Surface treatments modified the surface topography of glass fiber posts. Conclusions The BD/RP-TiF4 4 wt/v% showed greater bond strength compared with the other groups. The TiF4 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF4 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.

Effects of surface treatments on changes in low-voltage SEM of polymers

1991 ◽  
Vol 49 ◽  
pp. 1038-1039
Author(s):  
J. Chang ◽  
S. Krause ◽  
W. Adams
Keyword(s):  
Surface Treatment ◽  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Low Voltage ◽  
Beam Current ◽  
Polymer Surfaces ◽  
Powder Sintering ◽  
Good Potential ◽  
Effect Of Surface ◽  
Surface Changes

The effects of surface treatment of polymers is important in many areas of technology. Polymer surfaces may be treated for a variety of reasons including: increased wettability for printing; improved fiber bonding in composites; and improved bonding in powder sintering. A variety of techniques are used to study surface changes after treatments including hydrophobicity, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Another technique which has good potential for surface characterization is the effect of surface treatment on the crossover voltage, “E2,” in low voltage SEM. E2 is the accelerating voltage at which there is 0 potential on surface of an insulator because the electron emission current is equal to the primary beam current. We have previously demonstrated that changes in E2 are correlated to changes in hydrophobicity. These results also correlated well with XPS and weight loss measurements. In this research we are reporting on the effects of surface roughness, chemical treatment and electrical discharges on changes in E2 for teflon (polytetrafluoroethylene).

Effect of surface treatments of jute fibers on the microstructural and mechanical responses of poly(lactic acid)/jute fiber biocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73373-73382 ◽  
Author(s):  
Mohammad Tahir Zafar ◽  
Saurindra Nath Maiti ◽  
Anup Kumar Ghosh
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Surface Treatment ◽  
Surface Treatments ◽  
Jute Fiber ◽  
Poly Lactic Acid ◽  
Interface Adhesion ◽  
Mechanical Responses ◽  
Jute Fibers ◽  
Effect Of Surface

The effect of surface treatment of jute fibers on matrix/fiber interface adhesion in PLA/jute fiber biocomposites was explored in terms of mechanical, morphological, thermal and thermo mechanical properties.

scholarly journals Effect of Surface Treatments on Push-out Bond Strength of Calcium Silicate-based Cements to Fiber Posts

2020 ◽  
Author(s):  
Amr Elnaghy ◽  
Ayman Mandorah ◽  
Ali Hassan ◽  
Alaa Elshazli ◽  
Shaymaa Elsaka
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Glass Fiber ◽  
Calcium Silicate ◽  
Surface Treatments ◽  
The Other ◽  
Fiber Posts ◽  
Glass Fiber Posts ◽  
Push Out ◽  
Effect Of Surface

Abstract Background: To evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts. Methods: Two brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post was divided into four groups and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF4 4 wt/v%. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed. Results: BD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF4 4 wt/v% showed the greater characteristic bond strength (σ0) (15.93) compared with the other groups. Conclusions: The BD/RP-TiF4 4 wt/v% showed greater bond strength compared with the other groups. The TiF4 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF4 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.

scholarly journals Improving Restorative Maintenance Practices for Mature Permeable Interlocking Concrete Pavements

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1588 ◽  
Author(s):  
Kirti Sehgal ◽  
Jennifer Drake ◽  
Tim Seters ◽  
William Vander Linden
Keyword(s):  
Surface Treatment ◽  
Low Impact Development ◽  
Surface Treatments ◽  
Concrete Pavements ◽  
Infiltration Capacity ◽  
Parking Lot ◽  
Treatment Technologies ◽  
Over Time ◽  
Effect Of Surface

Permeable Interlocking Concrete Pavements (PICP) are a Low Impact Development (LID) technology that reduce the total volume of stormwater discharge and peak flows from urban hardscapes. Over time, particulates accumulate in the PICP joints, decreasing the pavement’s surface infiltration capacity and negatively affecting its overall functionality. Maintenance with two surface treatment technologies, a hand-held power brush and pressure washer-used in combination with vacuum street sweepers were compared to maintenance with vacuum street sweepers alone at four PICP parking lots. Both surface treatments along with vacuum street sweeping significantly improved the restoration of infiltration capacity for the young (i.e., <4 years) PICP section. Pressure washing in combination with vacuum sweeping was effective for PICP sections with larger (13–14 mm) joint openings. Power brushing, however, provided inconsistent results between the PICP sections. The effect of surface treatments was not significant for older (i.e., >6 years) installations with small (3–4 mm) joint openings. Though surface treatment resulted in significant improvement with a pressure washer and vacuum street sweeper combination, usage intensity of the parking lot was deemed as an important factor in restoring infiltration capacity. These findings re-emphasize that regular maintenance is essential to ensure long-term hydraulic functionality of PICP.

scholarly journals Effect of Surface Treatments on Shear Bond Strength of Polyetheretherketone to Autopolymerizing Resin

2019 ◽  
Vol 7 (3) ◽  
pp. 82
Author(s):  
Kosuke Kurahashi ◽  
Takashi Matsuda ◽  
Yuichi Ishida ◽  
Tetsuo Ichikawa
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Adhesive Strength ◽  
Shear Bond Strength ◽  
Acrylic Resin ◽  
Surface Treatments ◽  
Treatment Conditions ◽  
Bond Strengths ◽  
Resin Treatment ◽  
Effect Of Surface

These days, new prosthodontic materials are appearing with the development of digitalization. Among these, the use of polyetheretherketone (PEEK) as the clasp of removable partial dentures has been proposed. The adhesive strength between the PEEK and acrylic resin influences the probability of denture fracture. To investigate the effect of PEEK surface treatments on the shear bond strength to acrylic resin, five surface treatment conditions of PEEK were analyzed: 1. no treatment; 2. ceramic primer application; 3. Al2O3 sandblasting; 4. Rocatec; and 5. Rocatec with ceramic primer application, comparing with a metal primer-treated Co-Cr alloy. Two kinds of autopolymerizing resin (Unifast II and Palapress Vario) were used as bonding materials. The specimens were evaluated to determine the bond strength. Rocatec treatment with ceramic primer application yielded the highest bond strengths (12.71 MPa and 15.32 MPa, respectively, for Unifast II and Palapress Vario). When compared to a metal primer-treated Co-Cr alloy, the bond strength of PEEK to Unifast II was similar, whereas it was about 60% of that to Palapress Vario. Rocatec treatment, combined with ceramic primer, showed the highest bond strength of PEEK to acrylic resin. Treatment of PEEK will enable its use as the clasp of removable dentures and the fixation of PEEK prostheses.

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