Blistering Mechanism Research Articles

Lateral stress induced blistering of tungsten exposed to deuterium plasma

Surface blistering on tungsten under deuterium plasma exposure has been well known and investigated intensively in the last decade. However, the mechanism of the blistering is still unclear. There have been mainly two different models proposed: the gas driven model and lateral stress model. In this work, we designed an experiment to address this issue. Tungsten disc samples were prepared using twin-jet electro-polishing. The specimens were under deuterium plasma exposure to study the thickness effect on the surface blistering. The results showed that blistering was rarely observed on the surface around the inner edge of the central perforation with thickness of ∼100–500 nm. The blisters started to appear on the surface when the thickness was about 10 μm. Both the number and size of the blisters increased further on the outer surface with further increase in thickness. This trend was not obvious as the thickness increased up to above 180 μm. The diffusion depth of D in this work was calculated to be 8.5 μm. These results affirmed the lateral stress model as the surface blistering mechanism.

Surface blistering and D desorption in high-energy-rate forging W, W-Y2O3, W-TiC exposed to deuterium plasma

Pure tungsten (W) and two representative W alloys of W-1 wt.%Y2O3 and W-0.5 wt.%TiC were subjected to deuterium (D) plasma exposure at a fluence up to 1 × 1026 D/m2 at 400 K to evaluate their surface blistering and D desorption behaviors. Thermal desorption spectroscopy (TDS) results revealed that high-temperature desorption peaks (> 650 K) dominated in HERF-W, whereas the two W alloys featured higher intensities of low-temperature D desorption peaks (< 650 K). Even at a low D implantation fluence of 5 × 1023 D/m2, extensive blisters were evident on the surface of pure W, while no discernible blisters were detected on the surface of W-1 wt.%Y2O3 and W-0.5 wt.%TiC, even with a fluence exceeding 2 × 1025 D/m2. Microstructure analysis indicated that the relatively large grain size and limited intrinsic defects in HERF-W were the primary reasons for the early formation of D-induced blisters and subsequent high-temperature desorption of these trapped D, compared to those of two other W alloys. A focus ion beam (FIB)-SEM technique was employed to explore the mechanisms of blistering. Results revealed that the cavities beneath blisters were primarily located along grain boundaries, and coarse blisters were formed by the merging of several small ones. This work provides insight into the relationships among material microstructures, D-induced blistering and D desorption in W-based materials, thus offering valuable guidance for the design of W materials with high resistance to D-induced damages.

Bi-layer in-situ phosphorus doped poly-Si films by PECVD for blistering-free high-efficiency industrial TOPCon solar cells

The passivating contact concept stands out as one of the most promising and industrially viable photovoltaic (PV) technologies. Further improving the quality of physical contact has become a focus of ongoing research. The film blistering issue has been identified as one of the major bottlenecks for the polysilicon (poly-Si) films deposited by the PECVD approach. In this study, we investigated how the in-situ phosphorus (P) doping level within the poly-Si films contributes to the occurrence of blistering. Our investigations into the film blistering mechanisms reveal that a high in-situ P-doping suppresses hydrogen release levels and reduces the accumulation of residual stress during annealing, which leads to the blistering-free appearance, especially observed in heavily P-doped poly-Si films. However, as excessive P-doping could weaken the interfacial passivation quality, we propose a bi-layer structure of P-doped poly-Si films which allows the doping profile to be tailored and maintain good quality passivating contacts. Based on the bi-layer structure, we fabricated industrial-sized tunnel oxide passivated contact (TOPCon) solar cells, which attained an average efficiency of 23.84%. Our work not only presents a promising strategy for improving the performance of passivating contacts via the PECVD approach but also underscores the significant potential for its widespread implementation in industrial TOPCon solar cell manufacturing.

Mechanism of blistering of deformed coil coated sheets in marine climate

The tendency to blistering of coil coated steel sheets after deformation was investigated in both accelerated tests and marine climate. Corrosion processes played a crucial role in the blistering mechanism in deformed areas and blistering increased with induced strain. The inferior performance in deformed areas was associated mainly with higher permeability of organic coatings due to formation of additional defects. Localized water uptake measurements by the parallel plate capacitor technique were successfully applied to quantify the total damage to protective coatings induced by deformation. A link was found between blistering behaviour and the relative increase in water uptake.

Key parameters and mechanism of blistering of coil-coatings in humid-hot laboratory environments

Blistering of organic coatings on hot dip galvanized (HDG) steel is of high practical relevance, especially in warm-humid environments. The aim of this work was to study the key parameters of blister formation and growth by accelerated laboratory testing at 60 and 70 °C. Following a statistical design of Taguchi, the components of a polyurethane (PU) primer formulation were varied and applied to hot-deep galvanized (HDG) steel. The presence of a topcoat was found to be a precondition for blistering. Degradation started at microcracks within the primer and was significantly influenced by the adhesion between primer and topcoat. A high content of anticorrosive pigments resulted in enhanced blister formation, while blister growth is mainly controlled by mass transport processes and shows a strong temperature dependence. This study focuses on one specific blistering mechanism, osmotic blistering, which is indicated by blister kinetics and leachate analysis, estimated pressure values inside the blister are in reasonable agreement by using two different calculation approaches.

Formation mechanisms of surface blistering in AA6xxx rolled products: microstructure characterisation, ultrasonic analysis, and rolling tests results

ABSTRACT The source of surface blister defect in 6xxx series Al rolled products was studied. A blister defect, aligned with the rolling direction, was observed on the surface of the AA6xxx Al rolled sheets. It was indicated that the porosities and small microstructural inhomogeneities inside the cast ingots, identified by ultrasonic tests and metallography analysis, were not the origin of these surface defects. Pilot scale rolling trials indicated that the blister defects were correlated with the longitudinal internal casting cracks. The short side cracks in the cast ingots, covered by a thin Al oxide layer, were not healed and remained partially open after the rolling process. The unhealed cracks served as the nucleation sites for H2 precipitation during the later stages of the thermomechanical process, which were subsequently resulted from surface blisters on the AA6xxx Al rolled sheets.

Gene expression profiling of laminin α3-blocked keratinocytes reveals an immune-independent mechanism of blistering.

Laminin-332 pemphigoid is a rare and chronic autoimmune blistering disease which results in subepidermal blisters and erosive lesions predominantly localized to mucous membranes. As histologic inflammation is variable and non-complement-fixing IgG antibodies against laminin-332 are the predominant class of autoantibodies deposited at the epidermal basement membrane zone, we hypothesized that complement-independent pro-inflammatory and blistering pathways existed similarly to that previously shown in bullous pemphigoid. As autoantibodies to laminin α3 are most prevalent, we studied the major cellular response to blockade of laminin α3 using a well-characterized monoclonal antibody (P3H9-2). RNA-seq revealed upregulation of numerous desmosomal genes (DSG1, DSG3, DSC1, DSC3 and DSP) as well as KRT1 and KRT10. Additionally, P3H9-2-treated cells demonstrated downregulation of most hemidesmosomal genes. A pro-inflammatory response was not appreciated. Using pharmacological inhibitors, we identified both protein kinase C and NOTCH as key regulators of P3H9-2 induced differentiation. We lastly utilized 3D human skin equivalents to determine whether blockade of laminin α3 would lead to delayed blistering, consistent with keratinocyte differentiation. Significant blistering was noted after 72h of treatment, with only minimal separation at 24h. In summary, blockade of laminin α3 alters keratinocyte differentiation, representing a potential complement-independent mechanism of blistering.

Formation and elimination mechanism of thermal blistering in Al2O3/Si system

Formation and elimination mechanism of thermal blistering in Al2O3/Si system

Paint Blistering Mechanism of Steel Painted with Paint System Containing Inorganic Zinc Rich Paint

Paint Blistering Mechanism of Steel Painted with Paint System Containing Inorganic Zinc Rich Paint

Dependence of blistering and deuterium retention on damage depth in damaged tungsten exposed to deuterium plasma

The effect of different damage depth on blistering and deuterium (D) retention has been investigated in heavy-ion-damaged tungsten (W) with exposure to D plasma (40 eV, 1 × 1022 ions m−2 s−1) at 550 K. Different damage depths are realized via copper (Cu) ion irradiation with energies of 1, 3, and 6 MeV on W samples with the same calculated peak damage level of 0.5 dpa. The plasma-induced blister density reduces with increasing damage depth, which is explained based on the recently proposed dislocation nucleation mechanism of blistering. Comparison of D retention measured by nuclear reaction analysis (NRA) and thermal desorption spectroscopy (TDS) reveals that retention at depths larger than 7.4 μm—which is far beyond the ion damage depth—increases with damage depth. Such a phenomenon indicates a gradual increase of diffusion flux inside the damaged sample with the increasing damage depth. It is suggested that it originates from the observed difference in blister density. Besides the widely acknowledged enhanced D retention due to ion damage, this work shows a strong impact of the damage depth on blistering such as the blister density, and by which the D diffusion flux inside W and total D retention are further affected.

Investigation of the Blistering and Exfoliation Mechanism of GaAs Wafers and SiO2/Si3N4/GaAs Wafers by He+ and H+ Implantation

The thermally activated blistering and exfoliation of GaAs wafers and SiO2/Si3N4/GaAs wafers after H+ and He+ implantation is systematically investigated. Surface morphologies and microscopic defects are detected and analyzed by various measurements, such as optical microscopy (OM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Blistering and exfoliation are obtained on the surfaces of the GaAs and SiO2/Si3N4/GaAs wafers by either the exclusive implantation of 5 × 1016 He+/cm2 alone or by co-implantation of 0.5 × 1016 He+/cm2 and 4 × 1016 H+/cm2. Our experimental results show that the blistering and exfoliation of the SiO2/Si3N4/GaAs layer occurred when the concentration of He+ was relatively low, where fewer dislocations and nanocavities were created near the interface between the Si3N4 and GaAs layers.

Blistering Mechanism Analysis of Hydraulic Asphalt Concrete Facing

Two years after the Zhanghewan Pumped-Storage Power Station was put into operation, more than 500 blisters appeared in the asphalt concrete facing of the upper reservoir, and nearly half of them ruptured at the surface. The blistering mechanism of the asphalt concrete facing was studied in this paper. Through on-site inspection and coring inspection, it was found that the blistering was caused by the vapor pressure formed by the water enclosed in the middle of the impervious layer during high temperatures. Numerical analysis showed that the temperature 5 cm below the surface could reach 50–60 °C. Through numerical analysis and model tests, the internal water at this temperature may form a vapor pressure of 20 kPa. Finally, the blister size of the asphalt concrete facing at this temperature and pressure was studied with a model test. The possible sources of moisture inside the impervious layer were also analyzed through a core test, which found that moisture was most likely to be introduced by water spraying during rolling.

The Diagnosis and Blistering Mechanisms of Mucous Membrane Pemphigoid.

Mucous membrane pemphigoid (MMP) is a mucous membrane-dominated autoimmune subepithelial blistering disease that is caused by autoantibodies against various autoantigens in basement membrane zone (BMZ) proteins, including collagen XVII (COL17). Clinicians face diagnostic problems in detecting circulating antibodies and targeted antigens in MMP. The diagnostic difficulties are mainly attributed to the low titers of MMP autoantibodies in sera and to heterogeneous autoantigens. Additionally, no unanimous diagnostic criteria have been drawn for MMP, which can result in delayed diagnoses or misdiagnoses. This review aims to integrate and present currently available data to clarify diagnostic strategies and to present diagnostic criteria for MMP. The ultimate blistering mechanism in MMP has not been elucidated, and such mechanism is especially obscure in COL17-type MMP. In bullous pemphigoid (BP), which is the most common autoimmune subepidermal blistering disease, some patients show oral lesion as well as predominant skin lesions. However, there is no fundamental explanation for the onset of oral lesions in BP. This article summarizes innovative research perspectives on the pathogenesis of oral lesions in pemphigoid. Finally, we propose a potential pathogenesis for COL17-type MMP.

The direct binding of collagen XVII and collagen IV is disrupted by pemphigoid autoantibodies

The basement membrane zone (BMZ) is framed by hemidesmosomes and extracellular matrix (ECM) including collagen IV (COL4). Hemidesmosomes are multiprotein complexes that include collagen XVII (COL17). BMZ proteins can be targeted in autoimmune subepidermal blistering diseases, e.g., pemphigoid targeting COL17. The blistering mechanisms in pemphigoid have not been fully elucidated, especially in mucous membrane pemphigoid (MMP), which mainly affects the mucosa. In this study, we showed that oral lesions in pemphigoid may be attributed to the inhibition of protein–protein interactions by autoantibodies. Using immunoprecipitation, we revealed that COL17 directly binds to COL4 in normal human keratinocytes and normal human oral keratinocytes. In particular, the C-terminus of COL17 is binding site to COL4 in oral keratinocytes. The precise COL4-binding region on COL17 was determined by protein–protein binding assay to be from amino acid Gly1175 to Asp1340 on the C-terminus. MMP-IgG or mAb recognizing the C-terminus hindered the interaction of COL17 with COL4 in oral keratinocytes. Furthermore, keratinocyte adhesion strength to COL4-coated plates was significantly reduced by the treatment of mAb against the C-terminus. In addition, the inflammatory infiltrates around perilesions were significantly less in MMP compared to BP. These results indicate that pemphigoid IgG targeting the C-terminus plays a pathogenic role in blister formation in the oral mucosa to inhibit protein interactions with less inflammation.Collagen XVII directly binds to collagen IV at the basement membrane zone in both skin and oral mucosa. Mucous membrane pemphigoid autoantibodies targeting the C-terminus of collagen XVII hinder this binding and induce the detachment of basal cells in the oral mucosa. This mechanism leads to oral lesions that show less inflammation than the skin lesions show.

Influence of Inorganic Zinc Primer on Under-film Corrosion Simulation Parameters Based on Cellular Automaton

Osawa et al. (2016) developed a two-dimensional cellular automaton (CA) for under-film corrosion analysis and succeeded in consistent analysis of coating film deterioration and corrosion depletion. In this study, epoxy coated steels with and without inorganic zinc primer were prepared, and the panels having one scribe were subjected to cyclic corrosion test (CCT). And the influence of inorganic zinc primer on CA parameters was investigated from the corrosion surface profiles. In the CCT, corrosion depth became unaffected by zinc as CCT test time passed. However, progress of corrosion in perpendicular direction from the scribe was greatly increased by absence of zinc. As a result of identifying the CA parameters, the increase of coating film deterioration acceleration rate A0, the decrease of shielding duration TS and the increase of acceleration factor of bare material fbare were required by the specification change from zinc coating to no zinc coating. In order to understand the change of these parameters value, the mechanism of corrosion and blistering of epoxy coated steels with and without inorganic zinc primer was discussed. And the validity of difference in value of CA parameters with zinc coating and no zinc coating was shown based on the mechanism.

SURFACE EROSION OF MULTILAYER FILMS BASED ON ZIRCONIUM AND SILICON NITRIDES IRRADIATED WITH HELIUM IONS

The article is devoted to the investigation of surface erosion of ZrN/SiNx multilayer films irradiated with He ions (30 keV) and annealed in vacuum at 600 °C. It was found that multilayer ZrN/SiNx films remain resistant to blistering and flacking when irradiated with He ions (30 keV) up to a dose of 8∙1016 cm–2. The influence of the thickness of the crystalline and amorphous layer on the surface erosion nature and degree of multilayer films as a result of post-radiation annealing at 600 °C are revealed. The possible mechanisms of blistering and flexing in multilayer systems ZrN/SiNx are discussed in the work. Работа посвящена исследованию процессов эрозии поверхности многослойных пленок ZrN/SiNx , облученных ионами He (30 кэВ) и отожженных в вакууме при T = 600 °С. Выявлено, что многослойные пленки ZrN/SiNx остаются устойчивыми к образованию блистеров и отшелушиванию при облучении ионами He (30 кэВ) до дозы 8∙1016 см–2. Обнаружено влияние толщины кристаллического и аморфного слоя на характер и степень эрозии поверхности многослойных пленок в результате пострадиационного отжига при T = 600 °С. Обсуждаются возможные механизмы блистеринга и отшелушивания в многослойных системах ZrN/SiNx .

Detailed mechanism of surface blistering in sour media

The known occurrence or absence of surface blistering (SB) are reminded, either in field failures or in HIC testing in the laboratory, i.e. in sophisticated fitness for purpose tests at low pH or in simplified acceptance tests at conventional pH values (NACE TM 0284). A previous analysis of charging severity is also reminded, together with the presence of temporary degassing barriers. Then, through an accurate modelling of charging transients, significant overshots of the hydrogen content close to surface are shown to be present soon after immersion when looking for the most resistant steels in HIC testing on full thickness samples, so that SB can be met alone in such tests. On commissioning in the field, their magnitude is necessarily much lower, so that in field failures, SB is always met together with SWC in the bulk. Conversely, overshots are totally unlikely with small specimens, short durations and medium severity, and SB is never reported in TM 0284 tests. They are also made impossible in the field by a progressive commissioning, and SWC is often reported alone in field failures. Such agreement in a very complex situation is indeed one more indirect proof of the protonic nature of dissolved hydrogen in steel.

Complement‐independent blistering mechanisms in bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease that clinically demonstrates tense blisters with widespread erythema, histologically demonstrates subepidermal blistering and immunologically demonstrates the presence of circulating autoantibodies against hemidesmosomal molecules. Complement activation has long been regarded as necessary for the generation of the BP. However, certain evidence has recently come to support non-complemental blistering mechanisms. The story of BP blistering mechanisms is a complicated one. This review mainly focuses on a specific blistering mechanism that highlights the role of complements in BP blistering.

On the mechanisms of hydrogen-induced blistering in RF-sputtered amorphous Ge

Hydrogenated amorphous germanium, a-Ge:H, is a material of interest for optoelectronic applications such as solar cells and radiation detectors because of the material's potential to extend the wavelength sensitivity of hydrogenated amorphous silicon. For such applications, the best structural quality is required. Here, we investigate the mechanisms of blister formation in a-Ge:H films obtained by RF (radio frequency) sputtering when submitted to annealing. By a Fourier transform IR spectroscopy study of the Ge–H stretching vibrations, it is found that annealing increases the density of GeH2 dihydrides residing on the internal surfaces of nanovoids which increase their size because of that. The thermal energy supplied by annealing also favours the breakage of the Ge–H bonds with consequent release inside the cavities of atomic H which then reacts to produce molecular H2. The expansion of the H2 gas causes the nanovoids to enhance their volume up to the formation of surface blisters. The presence of H2 in the blisters is confirmed by the activation energy for the onset of blistering as measured by Arrhenius plots. The reduced H content observed by elastic recoil detection analysis and secondary neutral mass spectrometry in the annealed samples where blister bursting took place further supports the hypothesis of H2 filling the blisters before they explode.

Surface and internal microstructure damage of He-ion-irradiated CLAM steel studied by cross-sectional transmission electron microscopy

Good understanding of blistering and embrittlement mechanism depends on good investigation of surface and internal microstructure damage of gas-ion-irradiated materials. Internal and surface microstructure of He+ ion irradiated CLAM steel were examined by cross-sectional transmission electron microscopy combining focused ion beam. Variation of helium bubble density and size distribution versus depth in CLAM steel after high dose helium irradiation at room temperature was investigated. The average size of helium bubble increased within 100–400 nm but decreased near the non-irradiated matrix with the increase of depth, while the density followed a reverse trend. The formation and growth mechanism of helium bubble is different at different irradiation depth. The formation of a zone of large bubbles under the surface is the main reason of surface blistering and flaking. Helium induced irradiation swelling and surface blistering at low temperature were also discussed.