Study On The Mechanism Of Salt In Air Dust On The Deliquescence Of Statues Or Murals

Sculptures and murals are precious cultural heritages in China,reflecting the artistic styles and social characteristics of different periods.They hold significant importance for our understanding of past art history.However,due to natural and human factors,sculptures and murals are suffering from varying degrees of damage,such as salt efflorescence,blisters,and peeling.Atmospheric dust deposition is one of the main factors causing damage to sculptures and murals.Dust continuously accumulates on the surface of sculptures and murals,affecting not only their aesthetic appearance but also causing corrosion due to the presence of soluble salts.Therefore,investigating the impact of dust deposition on sculptures and murals and studying the combined effects of dust deposition and other factors on the generation of hygroscopic damage to sculptures and murals are of great importance.In this article,by conducting destruction cycle experiments,the corrosion mechanism of dust deposition on sculptures and murals is studied,as well as the impact of dust deposition on hygroscopic damage of basecoat test blocks in different environments.The main conclusions are as follows:(1)Exploring the effects of salt content in dust on the damage of statues/murals in cyclic experiments shows that after one cycle(water-salt migration,freeze-thaw,acid spray,and drying),water-salt migration can be considered as the main cause of the decay of statues/murals.In the experiment,the impact on the coarse plaster layer is greater than that on the fine plaster layer,and under the same conditions,the dust in the air aggravates the damage to the statues/murals.With the increase of the number of cycles,serious alkali disease occurred in the 16 th cycle,during which the specimen expanded,and the water content,conductivity,and soluble salt content increased continuously,but the growth rate gradually slowed down.Compared with specimens without dust,dust had a greater impact on the statues/murals.Moreover,in terms of the types of specimens,the water content of desalted specimens was higher than that of non-desalted specimens,while the conductivity and ion content were the opposite.(2)Exploring the effects of different environments on the decay of statues/murals shows that the amount of dust has a certain effect on the decay of the same specimens,and the humidity in the air makes the specimens absorb moisture,causing water migration.The soluble salt content in the dust will also migrate from top to bottom into the specimens.The greater the amount of dust,the greater the impact on the decay of the specimens.Temperature has an effect on the decay of the same specimens,but it has a relatively small impact compared with other factors.Temperature mainly affects the speed of soluble salt migration,and there is a critical value of 25℃.After exceeding the critical value,the migration rate of soluble salt gradually decreases.Humidity has a significant effect on the decay of the same specimens.During the process of continued moisture absorption after the decay of the specimens stabilized,their water content,conductivity,and ion content gradually increased.Moreover,the higher the humidity,the greater the migration of soluble salt in the dust to the specimens.Water-salt concentration has a significant effect on the decay of the same specimens.The dust on the specimens and their surfaces undergo decay at the same time.When the migration liquid rises to the fine plaster near the bottom layer,the specimen absorbs moisture and saturates.The higher the water-salt concentration in the environment,the greater the migration of soluble salt from the dust to the specimens,and the stronger the damage.For the same specimen under different amounts of dust,temperatures,humidity levels,and water-salt concentrations,the size change of desalted specimens is greater than that of non-desalted specimens.However,in terms of the impact on the water content and the migration of soluble salt from the dust to the specimens,the impact on desalted specimens is greater than that on non-desalted specimens,while the impact on the conductivity and ion content of the specimens is greater for non-desalted specimens than for desalted specimens.(3)In the preservation and protection of sculptures and murals,the environment has a relatively significant impact.Controlling the temperature range between 15℃-20℃ and the humidity range between 45%-60% is beneficial for the preservation of sculptures and murals.At the same time,it is essential to regularly clean the dust on the surface of sculptures and murals,apply preventive treatments to sculptures and murals that have not yet been affected by salt damage,and carry out water absorption and desalination treatments for areas that have already suffered from salt damage to ensure the integrity of the sculptures and murals.