Becker Albert O.  — The State Research Institute for Restoration, Artist-Restorer of the Department of Scientific Restoration of Metal Works
E-mail: 113metal@gmail.com

Dubrovin Mikhail F. — Ph.D., The State Research Institute for Restoration, Leading Researcher of the Department of Scientific Restoration of Metal Works
E-mail: 113metal@gmail.com

The article analyzes information from the main published materials on the topic under study: Postnikova-Loseva M. M., Platonova N. G., Ulyanova B. L. Gold and Silversmithing of the 15th – 20th Centuries (section “Index of Hallmarks on Items Made of Precious Metals”), Ivanov A. N. Assaying in Russia (1700–1946). A Guide for Art Experts; Kovarskaya S. Ya. Works of Moscow Masters of the First Half of the 19th Century. Catalogue of the Collection of the State Historical and Cultural Museum-Reserve “Moscow Kremlin”; address calendars “All Moscow” for the second half of the 19th century and the Database of The State Research Institute for Restoration the “Russian Hallmarks on Items of Decorative and Applied Art Made of Precious Metals” on the working period of Moscow assay offices 19th-century assay masters. A comparative analysis of information from various published sources revealed discrepancies regarding the working period of 19th-century Moscow assay masters, as well as the composition of assay offices during this period. For the first time, a comparative analysis of aggregated information from various sources, including address calendars and The State Research Institute for Restoration Database, was conducted. As a result of this comparative analysis, the timeframes of assay masters' work were clarified, confirmed by photographs of the hallmark impressions of these assay masters, as well as information from Address calendars. This article has scientific and practical value for both museum staff and specialists involved in the examination and attribution of decorative and applied art items made from precious metals. The information published in the article is useful both scientifically, by clarifying the working periods of assay masters and their composition, and for the practical introduction of previously unknown assay master stamps into scientific circulation.

Assay marks of Moscow in the 19th century, assay masters of Moscow in the 19th century, comparative analysis of the working periods of assay masters of Moscow in the 19th century, the State Research Institute for Restoration Database, unknown assay marks of the 19th century, unknown assay masters of Moscow in the 19th century, working periods of assay masters of Moscow in the 19th century.

Dobrovolsky Sergey V. — Candidate of Technical Sciences, Associate Professor; Moscow Aviation Institute (National Research University), engineer of research department 204
E-mail: dobrovolskiy_s@mail.ru

Glukhovskaya Yulia I. — Moscow Aviation Institute (National Research University), specialist engineer of research department 204
E-mail: gljul@bk.ru

The article explores the possibilities of using gas-dynamic methods of forming a material for the restoration of metal objects. The disadvantages and advantages of the currently used additive restoration technologies are analyzed. The choice of the cold gas dynamic method is justified as the most suitable for restoration conditions, the features of its use and the limitations caused by the technology of its application are shown. Previous experiments have shown that the quality of the formed material depends on the solution of a multiparametric problem, the main parameters of which are the particle size, its mass, the temperature of the heterogeneous flow, the angle of incidence of the particle on the surface, the distance from the accelerator slice to the surface, the shape of the surface itself, surface preparation and particle material. Possible directions of using the cold gas dynamic method for the restoration of metal products are considered. The options for the development, design and manufacture of specialized restoration gas dynamic installations are being investigated. Analyzing the specifics of the method described in the article, the authors conclude that for each type of restored object, it is necessary to calculate, design and manufacture a heterogeneous flow accelerator taking into account the laws of gas dynamics. The calculation result of a heterogeneous flow accelerator used for the restoration of large flat surfaces is presented. An example of an accelerator that turns the flow at a right angle and an accelerator used to operate on internal cylindrical surfaces is given.

Cold gas dynamic method, erosion and corrosion wear, heterogeneous flow, heterogeneous flow accelerator, installation for forming material by cold gas dynamic method, particle of powder material, restoration of metal objects.

Kotelnikov Pavel N.  — artist-restorer of the highest category of metal works; The State Research Institute for Restoration, head of the department of scientific restoration of metal works
E-mail: 113metal@gmail.com

Kurakov Sergey V.  — Researcher engineer; Bauman Moscow State Technical University, Engineer I cat. of Museum
E-mail: kurakov@bmstu.ru

Makarova Anastasia S. — PhD. cult., restorer of the I cat.; the State Research Institute for Restoration, Academic Secretary
E-mail: aanpilogova@mail.ru

Samoilov Vladimir B. — Bauman Moscow State Technical University, associate professor of the Department of Materials Processing Technologies
E-mail: wladsam@mail.ru

This article addresses the determination of the applicability limits and efficacy of modern spraying technologies for the restoration of metal artworks exposed outdoors. The study presents a comprehensive analysis of the Cold Gas-Dynamic Spraying (CGDS) method, encompassing its development history, technological features, potential, and modern applications. The practical research is focused on the outdoor sculpture located in Moscow and Saint Petersburg that was restored using this cold spraying method. A detailed laboratory study was conducted on coating samples taken from the federally significant cultural heritage objects — the allegorical zinc-alloy sculptures “Water” and “Earth” (by V. I. Mukhina, N. G. Zelenskaya, A. M. Sergeev). A set of analyses, including on-site visual inspection, metallography, and electron microscopy, was performed to assess the current state of the studied coatings, their adhesion, microstructure, and to identify the primary degradation mechanisms. As a result, the key advantages and disadvantages of the CGDS method in restoration practice have been systematized, and practical recommendations for its application in preserving monumental metal sculpture have been developed. The findings are of significant applied value for selecting optimal technologies, designing restoration processes, and addressing damage to metal cultural heritage objects in aggressive outdoor environments. The article presents work carried out within the framework of a scientific topic (registration number NIOKTR 124031100828-6), implemented at the expense of the federal budget in 2025.

Parfenov Vadim A. — Doctor of Technical Sciences, associate professor; Saint-Peterburg Institute of History of Russian Academy of Sciences, leading research fellow;
Saint Petersburg Electrotechnical University, professor;
Immanuel Kant Baltic Federal University, professor
E-mail: vadim_parfenov@mail.ru

The article describes a new approach to the reconstruction of damaged and severely destroyed metal monuments, which is based on the use of the direct metal laser sintering technology. The results of experimental studies aimed at investigation of the possibility of its application are presented using the example of filling the losses on a fragment of a cast-iron fence of one of the tombstones of the XIX century in the Alexander Nevsky Monastery in St. Petersburg. This item is a cast decoration in the form of a multi-pointed star, which had multiple losses of elements. To reconstruct the “star”, its 3D laser scanning and computer 3D modeling were carried out. The 3D model obtained as a result of these works was transformed into a CAD model, which was used to manufacture the lost elements using a robotic laser machine. A nickel alloy powder with a granule size of 50–150 microns was used as a “building material” in the experiments. The melting of the metal powder was carried out using a continuous-wave fiber ytterbium laser with a wavelength of 1.06 microns and an output power of up to 80 watts. As a result of the high-precision movement of the laser beam along a given calculated trajectory, which led to the layered application of thin layers of molten metal, the missing elements of the “star” were reconstructed. Thus, the effectiveness of the proposed approach was proved. This work is the first experience of using laser additive technologies in Russia in the restoration of historical cast iron objects.

3D scanning, additive technologies, direct metal laser sintering, laser, metal monuments, reconstruction, restoration.

Karakurkchi Roman S. — the International Jewellery School; Director, Teacher of Stone Setting Techniques
E-mail: kr@jewelleryschool.com

Khasieva Elena A. — the International Jewellery School, Project Manager
E-mail: top@jewelleryschool.com

Plakhov Vladimir V. — metal artist, engraver, member of the Russian Guild of Weaponry Masters; the International Jewellery School, teacher
E-mail: shtixel.spb@gmail.com

The article is devoted to the technology of anodizing titanium — a method that turns this super-modern structural material into a palette for an artist. Special attention is paid to the physical and chemical basis of interference coloring, which occurs due to the growth of a layer of titanium dioxide of different thickness, which is achieved by regulating the voltage. The practical aspects of the application are being investigated, including the limited color palette (the inability to obtain black, red, and dark orange colors), difficulties with uniform coloring on embossed surfaces, and the impact of different titanium alloys on the final color. Titanium anodization technology, being a delicate process, opens the door to creating not only functional but also visually appealing products. Interference coloring, which is resistant to mechanical abrasion and UV fading, offers exceptional durability, making it an ideal choice for products that require both durability and aesthetic novelty. The most important conclusions are as follows: anodizing titanium allows the creation of unique, long-lasting color effects, but requires precise process control and skill to achieve artistic goals. The technology is successfully synthesized with traditional metalworking techniques, expanding the possibilities of the modern metal artist. It is concluded that titanium anodization has established itself as a 21st-century material for engineers and artists, due to its strength, durability, and aesthetic appeal.

Electrochemical oxidation, incision engraving, inlay, interference coloring, international jewellery school, knife “Gothic”, obron, oxide film, timascus, titanium anodization.