Inert Metal Research Articles

Investigations of Tungsten Inert Gas and Metal Active Gas Joints of SUS301L Stainless Steel: Electron Backscatter Diffraction Characterization and Fatigue Performance

Investigations of Tungsten Inert Gas and Metal Active Gas Joints of SUS301L Stainless Steel: Electron Backscatter Diffraction Characterization and Fatigue Performance

Natural corrosion-induced gold nanoparticles yield purple color of Alhambra palaces decoration

Despite its fame as a chemically inert noble metal, gold (alloys) may suffer degradation under specific scenarios. Here, we show evidence of electrochemically corroded gilded tin plasterwork in the Alhambra (Granada, Spain) driving spontaneously made gold nanospheres with the optimal size (ca. 70 nm) to impart purple color at the surface. Purple gold on damaged artworks is found sparsely, and its formation is not fully explained yet. We prove that our decayed gold/silver-tin ornament is due to sequential/coexisting galvanic corrosion, differential aeration corrosion, and dealloying of nonperfectly bonded and defect-based metals. Damage is enhanced by exposure to a chloride-rich atmosphere. A white gypsum coat applied during the 19th century to overlap the unaesthetic gilding assists observation of the gold-based purple color. Our work demonstrates gold dissolution, millimetric migration, physical translocation, and deposition as secondary pure gold nanospheres over a centurial time scale under natural environmental conditions.

Dissolution of metallic iridium powders in hydrochloric acid oxidizing media

Iridium is one of the most chemically inert platinum group metals. It is extremely resistant to many reagents, including alkaline and mineral acid solutions. This, combined with the physical properties of iridium, defines the spectrum of its practical applications. This paper demonstrates that metallic iridium powders of various dispersion degrees can be dissolved in hydrochloric acid media in one stage in the presence of hydrogen peroxide. The morphology, as well as the phase and chemical compositions were studied by means of transmission and scanning electron microscopy, X-ray diffraction analysis, adsorption measurements of specific surface area and chemical analysis. The study looked at refined (30–150 μm particles), highly dispersed (150–200 nm) and nanocrystalline (8–15 nm) iridium. It also examined the dissolution kinetics of iridium(0) with different specific surface areas at the temperatures of 190 to 210 oC. For all the studied samples, the dissolution process was established to be of kinetic nature, and the obtained experimental data can be perfectly described with the shrinking core model. The dissolution activation energy for refined, highly dispersed and nanocrystalline iridium(0) in hydrochloric acid solutions in the presence of hydrogen peroxide is 145, 108 and 88 kJ/mol, correspondingly. This way, it was proved that the activation energy tends to go down as the particles get smaller. It was confirmed that iridium is present in solutions in the form of chloride complexes of quadrivalent iridium. Thus, metallic iridium was converted into chloride forms in an environmentally friendly way, which makes it easier to perform analysis for refining purposes, as well as further synthesis of iridium complexes. This research was carried out as part of a governmental assignment allocated to the Institute of Chemistry and Chemical Technology at the Siberian Branch of the Russian Academy of Sciences (Project 0287-2021-0014) and using the equipment of the Krasnoyarsk Regional Shared Knowledge Centre, a part of the Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences.

High-Entropy Intermetallics Serve Ultrastable Single-Atom Pt for Propane Dehydrogenation.

Propane dehydrogenation has been a promising propylene production process that can compensate for the increasing global demand for propylene. However, Pt-based catalysts with high stability at ≥600 °C have barely been reported because the catalysts typically result in short catalyst life owing to side reactions and coke formation. Herein, we report a new class of heterogeneous catalysts using high-entropy intermetallics (HEIs). Pt-Pt ensembles, which cause side reactions, are entirely diluted by the component inert metals in PtGe-type HEIs. The resultant HEI (PtCoCu) (GeGaSn)/Ca-SiO2 exhibited an outstandingly high catalytic stability, even at 600 °C (kd-1 = τ = 4146 h = 173 d), and almost no deactivation of the catalyst was observed for 2 months for the first time. Detailed experimental studies and theoretical calculations demonstrated that the combination of the site-isolation and entropy effects upon multi-metallization of PtGe drastically enhanced the desorption of propylene and the thermal stability, eventually suppressing the side reactions even at high reaction temperatures.

Inerting Waste Al Alloy Dust with Natural High Polymers: Sustainability of Industrial Waste.

A large amount of waste dust will be produced in the process of metal grinding, resulting in a waste of resources and environmental pollution. Therefore, we present a new method of inerting waste aluminum (Al) alloy dust for recycling purposes. Three natural high polymers—starch, pectin, and hydroxypropyl cellulose—were selected to inert waste metal dust in order to prevent the alloy from hydrolyzing and keep the dust pure enough for reuse. The particles of the Al base alloy before and after dust reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infra-red (FTIR), and the relevant reaction mechanism was clarified. The hydrogen evolution test indicated that, across the temperature interval of 313–333 K, 0.75 wt% pectin inerted hydrogen evolution most efficiently (90.125%). XRD analysis indicated that the inerted product is composed of Al monomer and Al3Mg2, with no detectable content of Al hydroxide. The purity of the Al alloy dust was preserved. SEM and FTIR analyses indicated that the -OH, -COOH, and -COOCH3 functional groups in the high polymer participated in the coordination reaction by adsorbing on the surface of the waste Al alloy particles to produce a protective film, which conforms to Langmuir’s adsorption model. Verification of the inerted Al alloy dust in industrial production confirmed the possibility of reusing waste Al alloy dust. This study provides a simple and effective method for recycling waste Al alloy dust.

Au-Stabilized Nanoporous PdCuAu Alloys Exhibiting Outstanding Catalytic Activity and Durability for the Formic Acid Oxidation Reaction.

Metallic Pd is widely recognized as an efficient electrocatalyst for the formic acid oxidation reaction (FAOR), which unfortunately suffers from poor durability owing to Pd dissolution and CO poisoning. The present work describes an effective method to enhance Pd durability by alloying with Cu and Au. Cu could provide surface OH at low potentials to remove poisonous CO for improved CO resistance. Au, the most inert metal, was added to reduce Pd and Cu dissolution. Moreover, alloying with Cu and Au could also modulate the electronic structure of Pd which is just profitable for the FAOR. The constructed PdCuAu with a nanoporous structure exhibits a specific activity of 14.9 mA cm-2 and a Pd mass activity of 6012 A g-1, which is ∼15 times and ∼14 times higher than those of commercial Pd/C. While these two electrocatalysts were used as fuel cell anodes, the maximum power density of the PdCuAu anode (Pd loading 10 μg cm-2) is 93.2 mW cm-2 and the value of the Pd/C anode (Pd loading 1.2 mg cm-2) is 60.3 mW cm-2. The power efficiency of Pd has been notably increased by 185 times in this home-made nanoporous PdCuAu ternary alloy electrocatalyst.

Electro-chemo-mechanics theory in transfer printing of thin films in electrolyte solutions

Transfer printing of thin films on an electrode substrate such as graphene on as-grown metal substrates in an electrolyte solution environment by applying an electrical field has provided a facile manufacturing technique to attain a precise delivery and assembly of thin film-based structures in a broad range of materials. The technique is underpinned by the electro-chemo-mechanical interfacial delamination, yet the fundamental theory is lacking. In the present study, we have established a comprehensive electro-chemo-mechanics theoretical framework of film detachment from various electrode substrates in an electrolyte solution environment. The bubble nucleation and subsequent kinetic growth due to the electrolysis of solution are first proposed and incorporated into the crack propagation of interface to predict the delamination of film from inert metal electrode substrates. Then, the film detachment induced by electrochemical etching to both interfacial bonds of film/electrode substrates and electrode substrates with chemically active metal materials is systematically investigated. The etching resultant kinetic model of bond breaking and failure is developed and also coupled with the bubble growth-induced interfacial delamination to describe their synergistic effect on the film detachment from electrode substrates with both types of electrode materials and polarity (i.e. anode or cathode). Afterward, we have implemented the electro-chemo-mechanics models into finite element method though a subroutine program. Computational results show remarkable agreement with theoretical predictions for both delamination mechanisms of solution electrolysis and electrochemical etching, regardless of materials of films, substrates and electrolyte solutions, and also are well confirmed with experimental results from literature in a good consistency. Further, a mechanical peeling force model equivalent has been developed to quantitatively estimate the electrochemical reaction-induced delamination and to discuss the application capacity of electrical field assistant transfer printing. The established electro-chemo-mechanics theory is expected to lay a foundation for quantitative understanding and controlling of transfer printing of thin films by the electrochemical field.

Enhanced Contrast of WO3-Based Smart Windows by Continuous Li-Ion Insertion and Metal Electroplating.

The electrochromic WO3 smart window based on an aqueous electrolyte shows an excellent liquid/solid interface and thus can achieve a fast electrochromic response, while the aqueous electrolyte has a limited electrochemical window, which probably induces the H+ reduction and degrades the practical application. Here, we propose a strategy to modify the traditional Li+ acidic aqueous electrolyte by adding some selective inert metal ions, which not only improve the electrochromic performance but also avoid the possible production of hydrogen bubbles due to the broadened electrochemical window. Furthermore, reversible electroplating of inert metal ions will occur, leading to an enhanced optical transmission change of up to 77.5% at 500 nm and 70.4% at 700 nm. This combination of Li-ion insertion and metal electroplating in the ESW device makes it superior to all of the previous reports. The device also demonstrates high stability and high electrochromic efficiency after 1000 cycles. The current study not only emphasizes the rational design for aqueous electrolytes but also demonstrates a practical way to realize an excellent electrochromic window for practical applications.

Accurate equation of state of rhenium as pressure scale up to 130 GPa and 3200 K

The equations of states (EOSs) of inert metals are generally used as pressure scales in a high-pressure experiment. However, the thermodynamic model and the method used to constrain the parameters of the EOSs of these metals may cause pressure deviations of up to 7% at 100 GPa and room temperature, and even higher at higher pressures and higher temperatures. In this study, we provide a new approach for obtaining accurate EOS of inert metals. First, we use a set of thermodynamic models, within the quasi-Debye framework, to describe the thermodynamics. Second, both the volume vs pressure data from the shock compression experiment and the volume vs sound velocity data from the static compression experiment are used to constrain the parameters in the EOS formula. In the fitting process, a weighted least-square method based on the uncertainty of these data is used. The calculated Grüneisen parameter shows a strong dependence not only on volume but also on temperature. The variation of the Grüneisen parameter of Re can increase by up to 7% per 103 K under the same volume, which means the previous temperature-independent approximation of the Grüneisen parameter may cause an underestimate of the pressure at high temperature. The pressure–volume–temperature EOS of Re up to 140 GPa and 3200 K is established, which can be used as a high-pressure and high-temperature pressure gauge in the future.

Predicting Cardiovascular Stent Complications Using Self-Reporting Biosensors for Noninvasive Detection of Disease.

Self‐reporting implantable medical devices are the future of cardiovascular healthcare. Cardiovascular complications such as blocked arteries that lead to the majority of heart attacks and strokes are frequently treated with inert metal stents that reopen affected vessels. Stents frequently re‐block after deployment due to a wound response called in‐stent restenosis (ISR). Herein, an implantable miniaturized sensor and telemetry system are developed that can detect this process, discern the different cell types associated with ISR, distinguish sub plaque components as demonstrated with ex vivo samples, and differentiate blood from blood clot, all on a silicon substrate making it suitable for integration onto a vascular stent. This work shows that microfabricated sensors can provide clinically relevant information in settings closer to physiological conditions than previous work with cultured cells.

Reversible On/Off Switching of Lactide Cyclopolymerization with a Redox-Active Formazanate Ligand.

Redox-switching of a formazanate zinc catalyst in ring-opening polymerization (ROP) of lactide is described. Using a redox-active ligand bound to an inert metal ion (Zn2+) allows modulation of the catalytic activity by reversible reduction/oxidation chemistry at a purely organic fragment. A combination of kinetic and spectroscopic studies, together with mass spectrometry of the catalysis mixture, provides insight in the nature of the active species and the initiation of lactide ring-opening polymerization. The mechanistic data highlight the key role of the redox-active ligand and provide a rationale for the formation of cyclic polymer.

Strategies and Methods of Modulating Nitrogen-Incorporated Oxide Photocatalysts for Promoted Water Splitting

ConspectusThe conversion of solar energy to chemicals and the storage of this energy is one of the most promising routes to realizing a “carbon zero” society, for which particulate photocatalytic water splitting to produce hydrogen has been considered to be a clean potential route. For this purpose, many d0 and d10 metal-based nitrogen-incorporated oxide (including nitrogen-doped oxide and oxynitride) semiconductor photocatalysts have been developed as good candidates to harvest major visible regions of solar light and to exhibit suitable energy levels to drive water splitting. Compared to the oxide-type photocatalysts, valence bands of the nitrogen-incorporated oxide can be upshifted in consideration of the lower electronegativity of nitrogen atoms concerning the oxygen atoms.However, a high-temperature nitridation process was needed to introduce nitrogen atoms into the metal oxide lattice. Because of the poor charge balance of the N3– substitution for O2– and the strong reducing effect of the active nitrogen species at high temperature, the nitriding process tends to introduce both anionic vacancy defects as well as low-valent metal ion defects. In addition, the crystal size of (oxy)nitrides synthesized through high-temperature nitridation is generally large, and there is a lack of an effective charge-separation driving force within the bulk of the (oxy)nitrides. Because of the scarcity of surface catalytic sites, the photocatalytic activity of the (oxy)nitrides is rather low.Recently, our group has been devoted to addressing the above key challenges, especially for the d0-metal-based (oxy)nitrides. The new preparation routes and/or methods were carried out to enhance the nitration kinetics for the synthesis of (oxy)nitrides with low-defect concentrations and further fabricate some novel metal (oxy)nitrides. The doping strategies were developed to suppress the generation of low-valent metal ion defects. A one-pot nitridation strategy was developed to construct the type II heterostructures of two metal oxynitrides to enhance their charge separation, and a strategy for the surface modification of metal oxynitrides with inert metal oxides was developed to promote the surface hydrophilicity and the cocatalyst dispersion. In addition, an intimate and strengthened interface between the cocatalyst and the metal oxynitride photocatalyst was achieved by a sequential cocatalyst decoration method, and it was demonstrated that the strengthened interface is beneficial to enhancing the surface charge separation efficiency. Benefitting from these methods and strategies, some novel visible-light-responsive materials have been exploited for promising water splitting, and remarkably improved water splitting performances have been achieved on some typical d0-metal-based (oxy)nitrides regardless of H2/O2-evolving half-reactions and Z-scheme overall water splitting (Z-OWS) reactions. In this Account, we will give a concise summary of these methods and strategies, and the prospects of nitrogen-incorporated oxide photocatalysts for potential water splitting will be examined.

Numerical and Experimental Investigation of Heat Distribution and Residual Stress Variation on Stacked Thin Sheets of CRNO Electrical Steel Post Tungsten Inert Gas and Cold Metal Transfer Welding

Abstract The paper presents a numerical and experimental investigation on the stacking of thin, cold rolled nongrain-oriented (CRNO) electrical steel sheets post-tungsten inert gas (TIG) and cold metal transfer (CMT) welding for predicting the effects of TIG and CMT welding current on weld geometry, temperature field, and residual stress distribution in thin, stacked weld sheets. Numerical simulation of a transient nonlinear thermal three-dimensional (3D) element based on actual weld conditions was carried out using ansys software by employing a moving heat source model based on a 3D Gaussian distribution to predict changes in temperature. As a result of the thermal history provided by the model, a mechanical analysis is performed to determine the residual stress distribution and the surface distortion in the element. A significant increase in weld penetration and weld width of the samples was observed with the increase in welding current, as well as a change in the temperature field in the weld zone. Moreover, both the experimental and numerical data are consistent in their estimation of the generation of residual stresses in the weld samples. A numerical model is presented for predicting the thermomechanical behavior of TIG and CMT welded stacked CRNO structures in the stator core of electric motors.

Functionalized Concave Cube Gold Nanoparticles as Potent Antimicrobial Agents against Pathogenic Bacteria.

Gold (Au) is an inert metal in a bulk state; however, it can be used for the preparation of Au nanoparticles (i.e., AuNPs) for multidimensional applications in the field of nanomedicine and nanobiotechnology. Herein, monodisperse concave cube AuNPs (CCAuNPs) were synthesized and functionalized with a natural antioxidant lipoic acid (LA) and a tripeptide glutathione (GSH) because different crystal facets of AuNPs provide binding sites for distinct ligands. There was an ∼10 nm bathochromic shift of the UV-vis spectrum when CCAuNPs were functionalized with LA, and the size of the as-synthesized monodisperse CCAu nanoparticles was 76 nm. The LA-functionalized CCAu nanoparticles (i.e., CCAuLA) showed the highest antibacterial activity against Bacillus subtilis. Both fluorescence images and scanning electron microscopy images confirm the damage of the bacterial cell wall as the mode of antibacterial activity of CCAuNPs. CCAuNPs also cause the oxidation of bacterial cell membrane fatty acids to produce reactive oxygen species, which pave the way for the death of bacteria. Both CCAu nanoparticles and their functionalized derivatives showed excellent hemocompatibility (i.e., percentage of hemolysis is <5% at 80 μg of AuNPs) to human red blood cells and very high biocompatibility to HeLa, L929, and Chinese hamster ovary-green fluorescent protein (CHO-GFP) cells. Taken together, LA and GSH enhance the antibacterial activity and biocompatibility, respectively, of CCAu nanoparticles that interact with the bacteria through Coulomb as well as hydrophobic interactions before demonstrating antibacterial propensity.

Inert metal induces the modulation of unsaturated aldehyde absorption mode for enhanced selective hydrogenation.

Selective hydrogenation of α,β-unsaturated aldehydes to obtain a high yield of unsaturated alcohols is important in industrial production. This is still a great challenge because it is thermally more favorable for the hydrogenation of CC than for the CO bond. Various strategies have been developed to optimize the catalysts for improving selectivity but are usually accompanied by the sacrifice of catalytic activity. Herein, we adopt the inert metal inducement strategy to synthesize a series of Ir-M alloy nanoparticle catalysts. The optimal catalyst IrCd5 exhibits impressive catalytic performance in the selective hydrogenation of cinnamaldehyde, achieving 96.7% conversion with 94.3% selectivity for cinnamal alcohol, which is far superior to that of the Ir counterpart. Furthermore, the H2 temperature-programmed desorption (H2-TPD) test, styrene-TPD test, surface valence band test and density functional theory calculations demonstrate that the adsorption mode of cinnamaldehyde shifted from parallel to vertical configurations after introducing an inert metal. Compared to Ir, the weaker adsorption of alkene and stronger adsorption of the substrate for IrCd5 lead to the prior adsorption and hydrogenation of the CO bond, thus elevating the selectivity of the cinnamal alcohol. This strategy disperses precious metal nanoparticles effectively, maximizes atomic utilization, and improves the selectivity, which provides a new avenue to design bimetal alloy catalysts for the selective hydrogenation of α,β-unsaturated aldehydes.

Influence of voltage, feed speed and CTWD on the corrosion resistance of Inconel 625 alloy coatings deposited by MIG

Annually, high investments are made in the maintenance of pipelines used in the oil industry around the globe. Thus, solutions are sought that combine low cost, reproducibility and properties that are consistent, mainly against corrosion. One of these is the use of materials that have high mechanical and anticorrosive properties in the form of coatings, which could be deposited by welding. The objective of this study was to evaluate the effects of different welding parameters on the corrosion resistance of coatings based on the Inconel 625 alloy, deposited by metal inert gas welding metal (MIG) process in API 5L X70 steel. The parameters were optimized using the factorial experimental design and the results analyzed by the Response Surface Methodology (RSM). Three deposits with ½ overlap were performed MIG, followed by a cross section cut in the samples for analysis of the dilution, iron content and corrosion resistance by potentiodynamic polarization (PP) through corrosion potential (Ecorr), corrosion current (Icorr) and polarization resistance (Rp). The coatings obtained presented values of the dilution ranging from 5.8% to 15.01%. The coating that presented lower dilution value, also was the one with lower Icorr and Fe, besides higher Rp and Ecorr, thus, greater corrosion resistance.

Analysis of The Removal Mechanism of Ferroalloy by Acidithiobacillus Ferrooxidans

Bio-machining technology is widely recognized as an environmentally friendly processing method for metals removal. In order to reveal the removal mechanism of ferroalloy corroded by Acidithiobacillus Ferrooxidans, ferroalloy workpieces were prepared by mixing 50% the powder of Fe with Co, Ni and Cu, and they were sintered with vacuum hot-pressing, A set of material removal experiments were carried out by shaking the ferroalloy with the bacterial strain culture solution of Fe3+ level at 5.5 g/L, and the material removal amount, surface morphology and roughness, and electrochemical characteristics of ferroalloy workpieces were determinated. The results showed that the Fe-based alloys containing Co, Ni, Cu, and Sn can be bio-machined, and the surface roughness of the ferroalloys significantly increased after machining. The material removal amount (MRA) of 8 hours of bio-machining ranked in the order of Fe50Co (42.3) >Fe50Cu (36.4) > Fe50Ni (21.6)>Fe50Sn (14.3). The MRA of each ferroalloy increased with the processing time, and the results could be fitted in a power function with machining time. In conclusion, the activity of the metal, the passivation on the alloy surface and the accelerated corrosion of the inert metal on the active metal were the three most important factors affecting MRA of ferroalloys. The additional reaction between Fe and newly generated metal ions by Fe3+, as well as the uneven reaction layer of workpieces was involved in the process of bio-machining.

Experimental Investigation of Similar &amp; Dissimilar Joints on Stainless Steel with TIG &amp; MIG Welded

Abstract: Now days, most of the structural fabrications possess welded joints that are produced using suitable welding technique. However, the joining of thick plates in a single pass welding is a cumbersome task to many fabricators. Likewise, the selection of welding technique, filler wire and welding condition for the similar and dissimilar welding of several metals is at the development stage. The similar and dissimilar metal joints of have been emerged as a structural material for various industrial applications which provides good combination of mechanical properties like strength, corrosion resistance with lower cost. Selections of joining process for such a material are difficult because of their physical and chemical properties. The stainless steel of similar and dissimilar material joints are very common structural applications joining of stainless steel is very critical because of carbon precipitation and loss of chromium leads to increase in porosity affects the quality of joint leads deteriorate strength. In the present study, stainless steel of grades 310 and 316 were welded by Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) welding with compound flux of 50 % SiO2 + 50 % TiO2 processes. The mechanical behavior like hardness, tensile strength and bending properties of similar and dissimilar metal joints were investigated. Keywords: Mechanical Properties, ATIG, MIG, SS310, SS316, Micro Structure.

Application of artificial substrate samplers to assess enrichment of metals of concern by river floodwaters to lakes across the Peace-Athabasca Delta

Study regionPeace-Athabasca Delta (PAD), northeastern Alberta. Study focusPotential for downstream delivery of contaminants via Athabasca River floodwaters to lakes of the PAD has raised local to international concern. Here, we quantify enrichment of eight metals (Be, Cd, Cr, Cu, Ni, Pb, V, Zn) in aquatic biota, relative to sediment-based pre-industrial baselines, via analysis of biofilm-sediment mixtures accrued on artificial substrate samplers deployed during summers of 2017 and 2018 in > 40 lakes. Widespread flooding in the southern portion of the delta in spring 2018 allows for assessment of metal enrichment by Athabasca River floodwaters. New hydrological insightsRiver floodwaters are not implicated as a pathway of metal enrichment to biofilm-sediment mixtures in PAD lakes from upstream sources. MANOVA tests revealed no significant difference in residual concentrations of all eight metals in lakes that did not flood versus lakes that flooded during one or both study years. Also, no enrichment was detected for concentrations of biologically inert metals (Be, Cr, Pb) and those related to oil-sands development (Ni, V). Enrichment of Cd, Cu, and Zn at non-flooded lakes, however, suggests uptake of biologically active metals complicates comparisons of organic-rich biofilm-sediment mixtures to sediment-derived baselines for these metals. Results demonstrate that this novel approach could be adopted for lake monitoring within the federal Action Plan.

Autoclave dissolution of platinum metals in hydrochloric acid oxidizing media

The paper provides the results obtained in the study of the features of metallic platinum, rhodium and iridium dissolution in hydrochloric acid solutions under hydrothermal autoclave conditions. Hydrogen peroxide was used as an oxidizing agent. Solid and liquid phases were brought into contact after reaching a predetermined temperature, which is critically important in the study of rhodium black and platinum plate dissolution kinetics due to the high rates of these processes. The concentrations of metals in solutions were determined by atomic absorption spectroscopy and inductively coupled plasma mass spectrometry. The forms of rhodium, iridium, and platinum chlorocomplexes in solutions were determined using the spectrophotometric method. As a result of the experiments, the conditions of platinum plate and rhodium quantitative dissolution (in the form of affined powder and a plate) were determined and it was shown that at 210 °C in 6M hydrochloric acid as a medium with the addition of 5 vol.% hydrogen peroxide, iridium taken in the form of affined powder went into the solution by 50 % within more than 50 h, while the platinum plate dissolved completely at 130 °C in about 120 min. Kinetic data analysis using the shrinking core model showed that rhodium black and affined rhodium and iridium powders dissolve under autoclave conditions in a kinetic mode. The results obtained can be used both in analytical chemistry for the quantitative determination of inert platinum metals and in refining production to improve the technology for processing raw materials containing platinum group metals (PGMs) and to optimize approaches to the synthesis of pure chlorocomplex compounds of PGMs.