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  • Author: Matilda Zemanová x
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Streszczenie

Skúmala sa kvalita utesnenia na báze zirkoničitých iónov pre anodicky oxidovaný hliník. Zisťovali sa optimálne podmienky utesňovania, pričom sa skúmali parametre: teplota a čas utesňovania a čas starnutia pripravených utesnených povlakov. Skúmala sa morfológia a zloženie pripravených povlakov. Zistilo sa, že parameter významne ovplyvňujúci kvalitu utesnených povlakov anodického oxidu hlinitého je teplota utesňovania. Pripravené povlaky sa potenciodynamicky skúmali v roztoku chloridových iónov. Neutesnený povlak v úzkom intervale potenciálov sa pasivuje, naopak utesnený neprejavuje pasivačné správanie.

Abstract

A comparison of the influence of two alloy pre-treatments and temperature treatments on the formation and composition of zirconium based conversion coating on the AA2024 alloy has been performed. The investigation employed mass changes, atomic force microscopy (AFM), XRD dispersive spectroscopy (EDX), infrared spectroscopy (IR) and electrochemical tests by open circuit potential (OCP) measurements. Pre-treatment using only alkaline etching is called alkaline pre-treatment. When alkaline etching is followed by de-oxidization in a phosphoric acid solution the process is called acidic pre-treatment. Conversion coatings were formed in Pragokor BL. IR analysis revealed the formation of a phosphate on the alloy surface. EDX analysis showed Mg dissolution. The Zr content increased with the temperature of the conversion coating formation. Both pre-treatment methods provided a phosphate layer on the alloy surface.

Abstract

The aim of the study was to find parameters of electrolytic colouring on tin basis to form uniform black coatings on anodized aluminium. A two steps electrolytic process consisting of aluminium anodization in a sulphuric acid electrolyte and colouring in tin acidic electrolyte was used. Among parameters influencing the colouring process, AC colouring voltage, composition of the counter electrode and agitation of the colouring electrolyte were studied. Spectrocolorimetry was applied to analyse the quality of the colouring. Thickness of the coloured and sealed anodized specimens was also evaluated. Optimal parameters for uniform colouring of anodized specimens were found. Unfortunately, colouring electrolyte on tin basis is susceptible to oxidation which negatively influences the colouring.