Sealing solution kit, two-step sealing method using the same and article

A sealing solution kit comprising:

• a) a medium temperature sealing solution;
• and
• b) a high temperature sealing solution;
• wherein the medium temperature sealing solution a), based on total volume of the medium temperature sealing solution, comprises:
• water;
• 0.6 to 2.6 g/L of fluoride ions;
• 2.0 to 5.0 g/L of a first ion selected from the group consisting of nickel ions, cobalt ions, chromium ions, cadmium ions and mixtures thereof;
• 0.03 to 1.3 g/L of a second ion selected from the group consisting of zirconium ions, titanium ions, silicon-containing ions, and mixtures thereof;
• an effective amount of surfactant;
• and
• wherein the high temperature sealing solution b) comprises, based on a total volume of the high temperature sealing solution:
• water and 0.1 g/L to 100 g/L of water-soluble polymer, the water-soluble polymer having a weight-average molecular weight of 5,000 g/mol to 400,000 g/mol, and the water-soluble polymer being selected from the group consisting of poly(meth)acrylic acid and its derivatives, polyether and its derivatives, polyamide and its derivatives, poly(sulfonic acid) and its derivatives and mixtures thereof.